What Is Biological Wastewater Treatment?
- Biological wastewater treatment harnesses the action of bacteria and other microorganisms to clean water. ...
- Aerobic Wastewater Treatment. ...
- MABR Treatment. ...
- Anaerobic Treatment. ...
- Further Treatment. ...
Full Answer
How can we treat waste water with biological methods?
Biological wastewater treatment is designed to degrade pollutants dissolved in effluents by the action of microorganisms. The microorganisms utilize these substances to live and reproduce. Pollutants are used as nutrients. A prerequisite for such degradation activity, however, is that the pollutants are soluble in water and nontoxic.
What is the biological treatment for waste water?
Explanation: Biological treatment of water, also called a secondary treatment of water, is the removal of organic waste from water using microbes. The extent of impurity in water is measured by its Biological Oxygen Demand (BOD). The microbes require oxygen to break down the organic impurities of water, and thus it helps in bringing down the total BOD of the water …
What are the biggest problems in wastewater treatment?
Apr 01, 2019 · In short, biological industrial wastewater treatment systems optimize the naturally occurring process of microbial decomposition to break down industrial wastewater contaminants so that they, along with other unwanted materials, can be removed. They also often replace (and are sometimes used alongside) physical and chemical treatments, which …
What is wastewater, and how is it treated?
The purpose of digestion is to reduce the amount of organic matter and the number of disease-causing microorganisms present in the solids. Biological treatment of waste can be carried out aerobically, process known as composting or anaerobically through anaerobic digestion.
What is biological wastewater?
Wastewater typically contains a buffet of organic matter, such as garbage, wastes, and partially digested foods. It also may contain pathogenic organisms, heavy metals, and toxins. The goal of biological wastewater treatment is to create a system in which the results of decomposition are easily collected for proper disposal.
Why is biological treatment used?
Biological treatment is used worldwide because it’s effective and more economical than many mechanical or chemical processes. Biological treatment usually is divided into aerobic and anaerobic processes. “Aerobic” refers to a process in which oxygen is present, while “anaerobic” describes a biological process in which oxygen is absent.
What is aerobic wastewater treatment?
Aerobic wastewater treatment processes include simple septic or aerobic tanks, and oxidation ditches; surface and spray aeration; activated sludge; oxidation ditches, trickling filters; pond and lagoon-based treatments; and aerobic digestion. Constructed wetlands and various types of filtration are also considered biological treatment processes. Diffused aeration systems may be used to maximize oxygen transfer and minimize odors as the wastewater is treated. Aeration provides oxygen to the helpful bacteria and other organisms as they decompose organic substances in the wastewater.
What is MABR treatment?
MABR Treatment. In recent years, technological advances have been transforming biological processes. One example is the membrane aerated biofilm reactor (MABR), which refines this process to use 90% less energy for aeration, typically the most energy-intensive stage of traditional biological treatment. In Fluence’s MABR treatment, air ...
What is nitrification denitrification?
Nitrification-denitrification is achieved by a biofilm that forms on the membrane. The result is an effluent suitable for irrigation or release into the environment. Most legacy plants around the world use activated sludge treatment or other older aerobic treatment processes.
Is biological wastewater treatment a complex process?
Biological wastewater treatment is a process that seems simple on the surface since it uses natural processes to help with the decomposition of organic substances, but in fact, it’s a complex, not completely understood process at the intersection of biology and biochemistry.
What are the different types of wastewater treatment?
Typically broken out into three main categories, biological wastewater treatment can be: 1 aerobic, when microorganisms require oxygen to break down organic matter to carbon dioxide and microbial biomass 2 anaerobic, when microorganisms do not require oxygen to break down organic matter, often forming methane, carbon dioxide, and excess biomass 3 anoxic, when microorganisms use other molecules than oxygen for growth, such as for the removal of sulfate, nitrate, nitrite, selenate, and selenite
What is a fixed bed wastewater system?
A well-engineered fixed-bed will allow wastewater to flow through the system without channeling or plugging. Chambers can be aerobic and still have anoxic zones to achieve aerobic carbonaceous removal and full anoxic denitrification at the same time.
How are suspended flocs removed from wastewater?
The suspended flocs enter a settling tank and are removed from the wastewater by sedimentation. Recycling of settled solids to the aeration tank controls levels of suspended solids, while excess solids are wasted as sludge.
How does a biological trickling filter work?
They work by passing air or water through a media designed to collect a biofilm on its surfaces. The biofilm may be composed of both aerobic and anaerobic bacteria which breakdown organic contaminants in water or air.
What is aerobic microbiology?
aerobic, when microorganisms require oxygen to break down organic matter to carbon dioxide and microbial biomass. anaerobic, when microorganisms do not require oxygen to break down organic matter, often forming methane, carbon dioxide, and excess biomass. anoxic, when microorganisms use other molecules than oxygen for growth, ...
When was the moving bed bioreactor invented?
Moving bed bioreactors, or MBBRs, invented in the late 1980s in Norway, already has been applied in over 800 applications in more than 50 countries, with approximately half treating domestic wastewater and half treating industrial wastewater.
When was activated sludge first used?
Activated sludge was first developed in the early 1900s in England and has become the conventional biological treatment process widely used in municipal applications but can also be used in other industrial applications.
What is membrane bioreactor?
Membrane Bioreactor (MBR) is the latest technology for biological degradation of soluble organic impurities. MBR technology has been in extensive usage for treatment of domestic sewage, but for industrial waste treatment applications, its use has been somewhat limited or selective. The MBR process is very similar to the conventional activated sludge process, in that both have mixed liquor solids in suspension in an aeration tank. The difference in the two processes lies in the method of separation of bio-solids. In the MBR process, the bio-solids are separated by means of a polymeric membrane based on microfiltration or ultrafiltration unit, as against the gravity settling process in the secondary clarifier in conventional activated sludge process. Therefore, the advantages of MBR system over conventional activated sludge system are obvious as listed below:
What is the difference between aerobic and anaerobic treatment?
Aerobic, as the title suggests, means in the presence of air (oxygen); while anaerobic means in the absence of air (oxygen). These two terms are directly related to the type of bacteria or microorganisms that are involved in the degradation of organic impurities in a given wastewater and the operating conditions of the bioreactor. Therefore, aerobic treatment processes take place in the presence of air and utilize those microorganisms (also called aerobes), which use molecular/free oxygen to assimilate organic impurities i.e. convert them in to carbon dioxide, water and biomass. The anaerobic treatment processes, on other hand take place in the absence of air (and thus molecular/free oxygen) by those microorganisms (also called anaerobes) which do not require air (molecular/free oxygen) to assimilate organic impurities. The final products of organic assimilation in anaerobic treatment are methane and carbon dioxide gas and biomass. The pictures in Fig. 1 and 2 depict simplified principles of the two processes.
What is a cyclic activated sludge system?
Cyclic Activated Sludge System (CASSTM) as the name suggests is one of the most popular sequencing batch reactor (SBR) processes employed to treat municipal wastewater and wastewater from a variety of industries including refineries and petrochemical plants . Aquatech has an agreement with AECOM (erstwhile Earth Tech), UK, the licensor of this technology to supply CASS™ technology in India on exclusive basis to both municipal and industrial markets.
What is biological treatment of industrial wastewater?
Biological treatment of industrial wastewater is a process whereby organic substances are used as food by bacteria and other microorganisms. Almost any organic substance can be used as food by one or more species of bacteria, fungi, ciliates, rotifers, or other microorganisms.
How do biological treatment systems work?
The first is to remove some of them by use of a pretreatment step. The second is to employ the process of gradual acclimation of the biological treatment system to the wastewaters.
What are the biological processes used in wetland systems?
The basic biological treatment processes used in the system include waste stabilization ponds and constructed wetland systems, trickling (or percolating) filter systems, and activated sludge systems. An aerobic stabilization pond is a large and shallow excavation in the ground, where the treatment of the waste occurs by natural processes involving the use of both bacteria and algae. In aerobic ponds, oxygen is supplied by natural surface re-aeration and by algal photosynthesis. Higher animals such as rotifers and protozoa are also present in the pond. Their main function is to predate on the bacteria, and to a lesser extent on algae, which helps in controlling the suspended solids (SS) concentration in the effluent. Ponds in which the stabilization of wastes is brought about by a combination of aerobic, anaerobic, and facultative bacteria are known as facultative stabilization ponds. The three zones in such ponds include a surface zone where aerobic bacteria and algae exist in a symbiotic relationship, an intermediate zone that is partly aerobic and partly anaerobic in which the decomposition of organic matter is carried out by facultative bacteria, and an anaerobic bottom zone in which accumulated solids are decomposed by anaerobic bacteria.
What is the acclimation step of wastewater treatment?
The acclimation step involves subjecting the biological treatment system, activated sludge, for instance, to gradually increasing levels of the toxic substances in the full strength wastewater, until full-strength wastewater is being treated.
What is aerobic stabilization pond?
An aerobic stabilization pond is a large and shallow excavation in the ground, where the treatment of the waste occurs by natural processes involving the use of both bacteria and algae. In aerobic ponds, oxygen is supplied by natural surface re-aeration and by algal photosynthesis. Higher animals such as rotifers and protozoa are also present in ...
What is the chemical treatment of ammonia?
One version of chemical-physical treatment has been to use chemical oxidation to destroy organics, ammonia, and cyanide and then to use activated carbon to remove unreacted substances as well as partially treated substances. Oxidation is accomplished by adding chlorine to the pretreated wastes in an aeration basin.
How much of the organic matter is removed by biological treatment?
Biological treatment is expected to remove 85% of the entering organic matter measured as BOD and suspended solids. Most biological processes exceed this level of performance because virtually all of the biodegradable material entering is at least partially degraded.
Why Treat Wastewater?
It's a matter of caring for our environment and for our own health. There are a lot of good reasons why keeping our water clean is an important priority:
Wastewater treatment
The major aim of wastewater treatment is to remove as much of the suspended solids as possible before the remaining water, called effluent, is discharged back to the environment. As solid material decays, it uses up oxygen, which is needed by the plants and animals living in the water.
Introduction
Goals
- The goal of biological wastewater treatment is to create a system in which the results of decomposition are easily collected for proper disposal. Scientists have been able to control and refine both aerobic and anaerobic biological processes to achieve the optimal removal of organic substances from wastewater.
Scope
- The biological processes used to treat wastewater include subsurface applications, such as septic or aerobic tank disposal systems; many types of aeration, including surface and spray aeration; activated sludge processes; ponds and lagoons; trickling filters; and anaerobic digestion. Constructed wetlands and various types of filtration are also considered biological treatment pr…
Subdivisions
- These processes are usually divided into anaerobic and aerobic processes. Aerobic refers to a process in which oxygen is present, while anaerobic describes a biological process in which oxygen is absent.
Applications
- Aerobic wastewater treatment processes include treatments such as activated sludge process, oxidation ditches, trickling filters, lagoon-based treatments, and aerobic digestion. Diffused aeration systems may be used to maximize oxygen transfer and minimize odors as the wastewater is treated. Aeration provides oxygen to the helpful bacteria and other organisms as t…
Technology
- An exciting new technology, the membrane aerated biofilm reactor (MABR), refines this process to use 90% less energy for aeration. Air is gently blown into a spirally wound membrane in a tank, with air on one side of the membrane and mixed liquor on the other. Nitrification-denitrification is achieved by a biofilm that forms on the membrane. The result is an effluent suitable for irrigatio…
Examples
- By contrast, anaerobic treatment uses bacteria to help organic material deteriorate in an oxygen-free environment. Lagoons and septic tanks may use anaerobic processes. The best-known anaerobic treatment is anaerobic digestion, which is used for treating food and beverage manufacturing effluents, as well as municipal wastewater, chemical effluent, and agricultural wa…
Treatment
- The type of biological treatment selected for wastewater treatment, whether aerobic or anaerobic, depends on a wide range of factors, including compliance with environmental regulations on discharge quality. Biological treatments are often supplemented with treatments including chlorination and carbon filtration, as well as technologies like reverse osmosis and ultrafiltration.
Research
- Researchers continue to look for ways to optimize conventional biological wastewater treatment. In one example, Finnish researchers added iron sulfate to wastewater before biological treatment to reduce phosphorous in tough-to-treat pulp mill wastewater. Other researchers have used ultraviolet light to remove challenging substances such as chemical residues and pharmaceutic…
Evolution
- So, while biological treatment has a long history, its continuing to evolve in ways that make it more effective, efficient, and available.