What is the role of bacteria in wastewater treatment?
Feb 02, 2022 · Most secondary treatment systems use aerobic bacteria that consume the organic components of the sewage. Some systems... The sewage is often mixed with air to facilitate decomposition as oxygen is critical for the growth of bacteria. This... During their growth period, these microbes consume a ...
What is bacterial decomposition in sewage treatment?
Facultative bacteria have the capability of living either in the presence or in the absent of oxygen. In the typical sewage treatment plant, oxygen is added to improve the functioning of aerobic bacteria and to assist them in maintaining superiority over the anaerobes.
What are the types of microbes used in sewage treatment?
Jul 23, 2018 · Common Microorganisms Used in Wastewater Treatment Aerobic Bacteria. Aerobic bacteria are mostly used in new treatment plants in what is known as an aerated environment. Anaerobic Bacteria. Anaerobic bacteria are used in wastewater treatment on a normal basis. The main role of these... Facultative. ...
What is the role of denitrifying bacteria in sewage treatment?
Biological wastewater treatment is the most common method of sanitation in the world. This technology uses different types of bacteria and other micro-organisms for the treatment and cleaning of polluted water. Wastewater treatment is as essential to human health as it is to environmental protection. Indeed, the use of these bacteria accelerates the treatment of …
What is a sewage treatment plant and how does it work?
A semi-solid waste or slurry byproduct of sewage treatment is called sewage sludge. Different processes like physical, chemical and biological meth...
What are the main steps in sewage treatment?
a. Primary treatment or Physical process b. Secondary treatment or Biological process
What is the major function of Microbes in Sewage Treatment?
Sewage is treated in sewage treatment plants (STPs) by the heterotrophic microbes present in the sewage before being disposed of in water bodies. M...
Explain types of microbes used in sewage treatment?
Aerobic Bacteria: These bacteria degrade the contaminants in the wastewater using free oxygen in the water, then turn into the energy that can be u...
Why is sewage treatment important?
Sewage treatment helps in reducing the rate of harmful contaminants that cause pollution of water and soil. Wastewater that is treated in these STP...
What are the phases of bacteria?
Five Phases of Bacteria Growth 1 During the lag phase, bacteria adapt to the environment, developing the required enzymes to digest nutrients. Bacteria break down nutrients with enzymes that only work in favorable conditions. Bacteria cannot survive if enzymes are not working properly. 2 Influent wastewater contains high levels of nutrients that bacteria use for growth and energy. Bacteria begin to grow and reproduce during the accelerated growth phase. Growing bacteria move about in search of nutrients, quickly multiplying. They do not settle to form floc. 3 During the declining growth phase, nutrient levels begin to drop and bacteria compete for nutrients. When food levels are low, bacteria slow down to conserve energy and do not grow or reproduce. Nutrients are used for energy and cell maintenance. 4 Bacteria levels remain constant during the stationary phase. They form a thick slime layer of waste products on the outside of the cell wall. This slime layer causes bacteria to clump together to form floc. 5 The number of bacteria reduces during the death phase. 1
What percentage of bacteria are in wastewater?
Bacteria account for 95% of the microorganisms in wastewater. They are single-celled microorganisms that are classified based on their response to oxygen. Aerobic bacteria use oxygen, which is added mechanically, to break down wastewater contaminants, converting it into energy.
How do bacteria use energy?
Bacteria use this energy to grow and reproduce. Anaerobic bacteria obtain oxygen from their food source. As anaerobic bacteria break down sludge, they produce methane gas. This methane gas can be used as an alternative energy source, called biogas, to fuel the wastewater treatment process.
What happens to bacteria during the stationary phase?
Bacteria levels remain constant during the stationary phase. They form a thick slime layer of waste products on the outside of the cell wall. This slime layer causes bacteria to clump together to form floc. The number of bacteria reduces during the death phase. 1.
How do bacteria break down organic material in wastewater?
Bacteria break down organic material in wastewater and form the floc that settles and separates solids from liquids. Controlling F/M ratio–a vital component to creating a favorable environment for wastewater bacteria–can be accomplished through the use of bioremediation products.
What happens when wastewater is removed?
Once most of the material is removed from the wastewater, microorganisms form floc and settle out as sludge. Some type of microorganism will always grow in the system. The organisms that will dominate will be the ones that are best suited to the environment.1. Microorganisms that are natural to the wastewater environment play a vital role in ...
How to find the amount of food available to microorganisms?
The amount of food available to microorganisms is calculated by the food-to-microorganism (F/M) ratio. The F/M ratio is the measurement of incoming food divided by the microorganisms (in lbs.) in the system. This is determined by dividing results of the BOD/COD test by the mixed liquor volatile suspended solids (MLVSS).
What is the role of bacteria in sewage treatment?
The role of bacteria in the sewage treatment process. One area of sewage treatment that is not well understood is the bacterial decomposition process. Bacteria may be aerobic, anaerobic or facultative. Aerobic bacteria require oxygen for life support whereas anaerobes can sustain life without oxygen. Facultative bacteria have the capability of ...
Do aerobic bacteria need oxygen?
Aerobic bacteria require oxygen for life support whereas anaerobes can sustain life without oxygen. Facultative bacteria have the capability of living either in the presence or in the absent of oxygen. In the typical sewage treatment plant, oxygen is added to improve the functioning of aerobic bacteria and to assist them in maintaining superiority ...
Why can't bacteria grow indefinitely?
In nature and in the laboratory, this growth cannot be maintained indefinitely, simply because the optimum environment of growth cannot be maintained. The amount of growth is the function of two variables: - environment and food. The pattern which actually results is known as the bacterial growth rate curve.
Why does the rate of reaction increase?
The rate of reaction may be increase by increasing the quantity of the substrate or temperature up to a certain point , but beyond this, the rate of reaction ceases to increase because the enzyme concentration limits it.
What are the roles of microorganisms in wastewater treatment?
The role of microorganisms in wastewater treatment helps to treat and purify wastewater and make it less harmful to the environment. While there are many different microbes used in sewage treatment, there are three well-known microbes that play an instrumental role in keeping sewage clean. Each of these types of bacteria help ...
Is wastewater bad for the environment?
Wastewater can be detrimental to the environment if left untreated. That’s because waste from humans and pets are a source of several types of waterborne diseases and bacterial contamination. Thanks in part to microorganisms, treating wastewater and sewage is possible. The role of microorganisms in wastewater treatment helps to treat ...
What is aerobic bacteria?
Aerobic Bacteria. Aerobic bacteria are mostly used in new treatment plants in what is known as an aerated environment. This bacterium uses the free oxygen within the water to degrade the pollutants in the wastewater and then converts it into energy that it can use to grow and reproduce.
Do aerobic bacteria need oxygen?
Unlike aerobic bacteria, this type of bacteria is able to get more than enough oxygen from its food source and will not require adding oxygen to help do its job. Phosphorus removal from wastewater is another benefit of anaerobic microbes used in sewage treatment.
What is the role of anaerobic bacteria in wastewater treatment?
The main role of these bacteria in sewage treatment is to reduce the volume of sludge and produce methane gas from it.
What are the causes of anaerobic bacteria?
The presence of bad bacteria (or the absence of good ones) can cause in particular: 1 Low biogas efficiency of the anaerobic digester 2 Poor flocculation and sedimentation 3 An excess of filamentous bacteria 4 Excess of phosphorus 5 Low nitrogen removal efficiency (NH4, NO3) 6 The production of unpleasant odours 7 Excess consumption of chemical products 8 In an anaerobic digester, foam production
Why is wastewater treatment important?
Wastewater treatment is as essential to human health as it is to the protection of the environment. The use of these bacteria accelerates the process of treating pollution on a small surface: the wastewater treatment plant.
What is biological wastewater treatment?
Biological wastewater treatment is the most common sanitation method in the world. This technology uses different types of bacteria and other microorganisms for the treatment and purification of polluted water. Wastewater treatment is as essential to human health as it is to the protection of the environment.
How long does it take for bacteria to colonize the environment?
The colonization of an environment by the needed bacteria and microorganisms necessary for the purification generally lasts between 4 and 8 weeks. Once again, it is the temperature that has the most influence on this growth time.
Can chlorine kill bacteria?
If this does not work, then it is possible to destroy these bacteria with chlorine. The problem is that it kills all bacteria. Then it will take a few weeks for normal conditions to be reached again. While the majority of operators continue to inject chlorine, we recommend the injection of dedicated bacteria.
What is the main source of wastewater?
Municipal and industrial effluent is the main source of wastewater. And thanks to the use of micro-organisms, we are able to degrade the content of these organic wastes as they are used as a source of food and energy to grow and multiply. You got it, bacteria are the heart of the process.
How does floc work?
The technique consists in recirculating a well-adapted combination of substrate and selected bacteria so that they settle very quickly. Under these favorable conditions, bacteria develop flocs or biofilms very quickly. Under these favorable conditions, bacteria develop flocs or biofilms very quickly.
Why is the environment of sewage treatment plant controlled?
The environment of the sewage treatment plant has to be controlled precisely because bacteria are sensitive to the oxygen level, pH level, temperature, and level of nutrient. In order for efficient degradation of biological matter to occur, these factors are controlled manually.
What is sewage treatment?
Sewage treatment is a process in which the pollutants are removed. The ultimate goal of sewage treatment is to produce an effluent that will not impact the environment [1] . In the absence of sewage treatment, the results can be devastating as sewage can disrupt the environment. The general processes of sewage treatment are primary, ...
How does tertiary treatment work?
In tertiary treatment, the removal of excess organic matter is enhanced by settling the sewage in a lagoon. This process is also aerobic, but it depends on the diffusion of oxygen because most organic matter has been degraded by secondary treatment [5] .
Why is oxygen important?
Oxygen level. Oxygen level is an important factor to secondary and tertiary treatment processes. Secondary treatment, oxygen is required as a terminal electron acceptor in organic matter degradation. For example, nitrification by Nitrosomonas and Nitrobacter species requires dissolved oxygen to occur [4].
What is the pH of nitrification?
They oxidize ammonium into nitrite. This bacterium prefers a pH around 6-9 and nitrify optimally at 20-30°C [4] .
Why is temperature important for bacteria?
Bacterial growth is sensitive to temperature because high temperature can increase the fluidity of the phospholipid bilayer which leads to cell lysis. However, bacteria are known to have higher enzymatic activity at higher temperature ...
How does acidity affect organic matter?
Acidity plays a crucial role in the breakdown of organic matter because pH affects the solubility of compounds which indirectly affect the accessibility by bacteria [8]. Also, bacteria responsible for organic matter degradation are sensitive to the pH of the environment. Extremely high or low pH levels are able to kill bacteria, ...
What Is a Biological Sewage Treatment System and How Does It Work?
While most sewage is treated by local municipalities, it is done so in various ways.
What is a biological sewage treatment system?
Sewage, or human-generated wastes, is typically treated by publicly owned treatment works (or POTWs), which are all either city, county, or regional facilities.
How does a biological sewage treatment system work?
For the most part, POTWs run their biological sewage treatment systems aerobically (which means they use bacteria that require oxygen to break down the wastes) using a process called “ activated sludge .”
Biological sewage treatment system variations
If you are able to wrap your head around the initial concept described above, you now understand about 80% of how biological sewage treatment systems work.
Can SAMCO help?
SAMCO has over 40 years’ experience custom-designing and manufacturing biological wastewater treatment systems, so please feel free to reach out to us with your questions. For more information or to get in touch, contact us here. You can also visit our website to set up a call with an engineer or request a quote.
How long does it take for a bacterial infection to grow?
The bacteria will grow itself and there is no need to “seed” the system with bacteria at the start. It can take 4-6 weeks for a system to get fully populated with bacteria, this is normal and it is ok to use your system immediately.
Can bacteria digest food?
Ideally the answer is no, naturally forming bacteria in your gut helps to digest food. This is no different to inside a sewage treatment plant. However, some people take pro-biotics to improve their gut flora. This is something people do when they think something is wrong. Inside a treatment plant, naturally forming bacteria normally do ...
Aerobic, Anaerobic and Facultative Bacteria
Food-To-Microorganism Ratio
- The amount of food available to microorganisms is calculated by the food-to-microorganism (F/M) ratio. The F/M ratio is the measurement of incoming food divided by the microorganisms (in lbs.) in the system. This is determined by dividing results of the BOD/COD testby the mixed liquor volatile suspended solids (MLVSS). If the mixed liquor is not held long enough for nutrient level…
Bioremediation
- The F/M ratio can be adjusted with bioremediation, which is a process of treating wastewater to encourage the growth of existing microorganisms. With biostimulation, supplemental nutrients, vitamins, minerals, organic acids, and pH buffers are introduced into wastewater to create a hospitable environment that stimulates naturally occurring microorganisms. Bioaugmentation, t…
Conclusion
- Bacteria break down organic material in wastewater and form the floc that settles and separates solids from liquids. Controlling F/M ratio–a vital component to creating a favorable environment for wastewater bacteria–can be accomplished through the use of bioremediation products. The presence and activities of bacteria and other microorganisms indicates the condition of wastew…
Citations
- T Glymph (2005). Wastewater Microbiology: A Handbook for Operators, https://www.iowaruralwater.org/tools_tips/toni_glymp/Bacteria-Protozoa.pdf
- Kentucky Department for Environmental Protection (2012). Types of Bacteria Used in Wastewater Treatment, https://kyocp.wordpress.com/2012/06/14/types-of-bacteria-used-in-wastewater-treatment/
- T Glymph (2005). Wastewater Microbiology: A Handbook for Operators, https://www.iowaruralwater.org/tools_tips/toni_glymp/Bacteria-Protozoa.pdf
- Kentucky Department for Environmental Protection (2012). Types of Bacteria Used in Wastewater Treatment, https://kyocp.wordpress.com/2012/06/14/types-of-bacteria-used-in-wastewater-treatment/
- R Fuller (2017). Food-to-Mass (F:M) Ratio, The Wastewater Blog, https://www.thewastewaterblog.com/single-post/2016/12/19/Food-to-Mass-Ratio
- LM Coelho, HC Rezende, LM Coelho, PAR de Sousa, DFO Melo, and NMM Coelho (2015). Bioremediation of Polluted Waters Using Microorganisms, https://www.intechopen.com/books/advances-in-bioremediation-...
