Biological processes for wastewater treatment
- Preliminary treatment. The preliminary treatment is essential for the removal of untreatable course materials,...
- Primary treatment. The basic principle of primary treatment is to remove the organic content like TSS (Total suspended...
- Secondary treatment. The secondary treatment provides the further removal of BOD (80-90%)...
How can we treat waste water with biological methods?
nature of toxicity associated with waste water. The classification of techniques for the removal or the reduction of the contaminants based on the need and the available technol ogy is as follows: 1. Biological treatment: Aerobic digestion (oxidation) of the effluent and anaerobic waste minimisation. 2.
What is the biological treatment for waste water?
Membrane technologies are gaining traction in industrial wastewater treatment due to their higher efficiency in treating chemical oxygen demand, biological oxygen demand, total suspended substance ...
What are the types of wastewater treatment processes?
Types of Effective processes to treat Wastewater:
- Biological water treatment: This method breaks down organic matter in the waste water by using decomposed biological methods carried out; microorganisms are also involved in metabolizing organic matter. ...
- Chemical Water Treatment: In this process chemicals are used to purify the water. ...
- Physical Water Treatment:
What is biological waste treatment?
Biological wastewater treatment is usually the second stage in the cleaning process and comes after larger particles have been removed through the filtering or settlement stages.
What are biological treatment methods?
There are two types of biological treatment process; aerobic and anaerobic. Biological wastewater treatment is an extremely cost effective and energy efficient system for the removal of BOD (Biological Oxygen Demand), since only micro-organisms are used.
What biological processes occur in STP?
Because there is ammonia now, the sewage treatment is going to include biological nitrification to remove the ammonia, which gives you nitrates. And after all the ammonia is converted to nitrates, bacteria—either anaerobic or anoxic—reduce all the nitrate and create nitrogen gas, which dissipates into the atmosphere.
Which of the following is a biological process?
the processes by which an organism has an observable effect on another organism of the same or different species. Also: cellular differentiation, fermentation, fertilisation, germination, tropism, hybridisation, metamorphosis, morphogenesis, photosynthesis, transpiration.
What is a secondary or biological treatment?
Secondary treatment removes the dissolved organic matter by the use of biological agents and hence, known as biological treatment. This is achieved by microbes which can consume and degrade the organic matter converting it to carbon dioxide, water, and energy for their own growth and reproduction.
What is the most studied system in MBRs?
When modeling biological reactions in MBRs, activated sludge processes for wastewater treatment are the most studied systems. To model the biological wastewater treatment process, a high number of state variables and process descriptions, mostly based on Monod type kinetics, have been used and combined in modeling structures.
What chapter does nutrient dosing in wastewater treatment?
Chapter 3, Reactivating Bacterial Community and Biochemical Events, demonstrated the nutrient exhaustion inside a bioreactor-based treatment process, and in Chapter 4 , Dosing With Product From the Waste: Use of Fractionsm we discussed in detail nutrient dosing. The reactivation of a nutrient exhausted bioreactor by nutrient dosing would be not only an eventual requirement, but also would arguably be the best possible method to improve the bioreactor’s performance.
What is biological wastewater treatment?
Biological wastewater treatment entails the use of an active microbial biomass to degrade soluble organic carbon, nitrogen, and phosphorus compounds in a manner that sustains the growth of the biomass.
How is oxygen supplied to wastewater?
In conventional aerobic biological wastewater treatment processes, oxygen is usually supplied as atmospheric air, either via immersed air-bubble diffusers or surface aeration. Diffused air bubbles (via fine bubble aeration) are delivered to the bulk liquid (as in an ASP, a biological/submerged aerated filter (BAF/SAF), fluidized bioreactors, etc.), or oxygen transfer occurs from the surrounding air to the bulk liquid via a liquid/air interface (as for a TF or a rotating biological contactor (RBC)).
What do thriving microbial assemblages feed on?
The thriving microbial assemblages feed on the root exudates for their metabolism and favor microbial oxidation of the azo dye’s reduced products that fasten their mineralization. The plants uptake some of the reduced and simplified products of dye, produced in the anaerobic region, for their growth.
Why are WWT processes so attractive?
WWT biological processes are very attractive due to their waste treatment properties and their capacity for generating biofuel from waste materials , which can be used for electrical energy generation [23,26].
When was the anaerobic filter invented?
Introduced by Coulter et al. in 1957 and developed by Young and McCarty in 1967, the anaerobic filter is a fixed-film biological wastewater treatment process in which a fixed matrix (support medium) provides an attachment surface that supports the anaerobic microorganisms in the form of a biofilm.
How does biological wastewater treatment work?
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. Degradation process can take place either in the presence of oxygen (aerobic treatment) or in the absence of oxygen (anaerobic treatment). Both these naturally occurring principles of effluent treatment give rise to fundamental differences in the technical and economic processes involved (Table 2 ).
What is phytoremediation in wastewater treatment?
Phytoremediation method: This is another biological method for wastewater treatment. The combination of two Latin words―plant and remedy―gave rise to the term phytoremediation. The plant, plant origin microbes, or associated microbiota are used to take up the contamination from soil or water.
Why do aerobic microorganisms need oxygen?
Aerobic microorganisms require oxygen to support their metabolic activity. In effluent treatment, oxygen is supplied to the effluent in the form of air by special aeration equipment. Bacteria use dissolved oxygen to convert organic components into carbon dioxide and biomass.
How is phytoremediation achieved?
The remediation is achieved either by retaining, elimination, or degradation in a natural way as it happens in an ecosystem. Phytoremediation is a cheaper, eco-friendly, and feasibly sustainable method for removal of dye pollutants. Moreover, the process requires little nutrient cost and also has aesthetic demand.
How is oxygen supplied to wastewater?
In conventional aerobic biological wastewater treatment processes, oxygen is usually supplied as atmospheric air, either via immersed air-bubble diffusers or surface aeration. Diffused air bubbles (via fine-bubble aeration) are added to the bulk liquid (as in an ASP, biological aerated filters (BAFs), fluidised bioreactors, etc.), or oxygen transfer occurs from the surrounding air to the bulk liquid via a liquid/air interface (as for a TF or rotating biological contactor (RBC)).
What is the resultant of cleavage?
The resultant of cleavage is lethal aromatic amine that can be later decomposed by the aerobic process [59,60]. Laccase is a small molecular weight, multicopper-containing enzyme that degrades dye substrate with less specificity.
How does biogas replace fossil fuels?
In its function as a regenerative energy carrier, biogas replaces fossil fuels in the generation of process steam, heat, and electricity. The composition and quality of biogas depend on both effluent properties and process conditions such as temperature, retention time, and volume load.
What are the two main types of wastewater treatment?
There are two main types of wastewater treatment: primary and secondary. Primary treatment is a fairly basic process that is used to remove suspended solid waste and reduce its biochemical oxygen demand in order to increase dissolved oxygen in the water.
Why is wastewater sent through a tertiary treatment?
Because all of the contaminants have not been removed , the wastewater is usually sent through a tertiary treatment process after the biological treatment. During this stage, heavy metals, nutrients, and other impurities are removed from the wastewater.
What is anoxic treatment?
Anoxic treatments help remove nitrates and nitrites, selenates and selenites, and sulfates from the wastewater. People are seeing this more in areas where nitrates and sulfates are a concern. It’s the best way to remove as many of them as possible. Anoxic treatments work without adding additional chemicals.
Why is aeration needed in wastewater treatment?
Aeration is needed to oxygenate the wastewater through the use of mixers and aerators. Aerobic treatments work faster and result in cleaner water than anaerobic treatments, which is why they are preferred. The most popular aerobic treatment is the activated sludge process.
How does aerated lagoon work?
Some facilities use aerated lagoons as opposed to the activated sludge process. With this method, the wastewater sits in a treatment pond, where it is mechanically aerated. Pumping oxygen into the pond will increase microbial growth and speed up the decomposition of organic matter.
What is the best way to treat wastewater?
The activated sludge process is one of the most efficient ways to biologically treat wastewater and it’s effective. Another popular aerobic treatment is the trickling filter process. During the trickling filter process, wastewater flows over a bed of rocks, gravel, ceramic, peat moss, coconut fibers, or plastic.
Why is industrial wastewater important?
Even industrial wastewater is going to contain contaminants. It’s important to properly clean water before releasing it into natural water sources. Too much phosphorus can cause algae blooms to take over the lake or pond. Algae will end up depleting the stores of oxygen fish and other aquatic creatures rely on.
What is the objective of biological treatment?
Objective of biological treatment. Coagulate and remove the non-settle able colloidal solids . Stabilize the organic matter. Reduce the organic matter. Remove the nutrients. In short, stabilize organic matter: convert organic matter to nonbiodegradable form so that it does not exert oxygen demand .
What is activated sludge?
Activated Sludge Process is the suspended-growth biological treatment process, based on providing intimate contact between the sewage and activated sludge.The Activated Sludge is the sludge obtained by settling sewage in presence of abundant O2 so as to enrich with aerobic micro-organisms.
What is Zoogloea bulking?
Zoogloea bulking – Zoogloea occur at high F/M conditions and when specific organic acids and alcohols are high in amount due to septicity or low oxygen conditions.
What is lagoon in water?
Lagoons are deep waste stabilization ponds -like bodies of water or basins designed to receive, hold, and treat wastewater for a predetermined period of time by artificial means of aeration.
How do facultative lagoons work?
Most facultative lagoons are designed to operate by gravity flow. The system is not maintenance intensive and power costs are minimal because pumps and other electrically operated devices may not be required.
Is sulfide toxic to activated sludge?
The washing of cement or lime trucks to a manhole, dumping of congealed diesel fuel to the sewer system, and overload of small systems with septage (which contains a high amount of organic acids and sulfides which can be toxic). Sulfide toxicity to activated sludge is more common than currently recognized.
How effective is biological treatment?
The biological treatment is effective in removing up to 95% of the BOD. Large tanks are required in order to eliminate the entire BOD, which is not feasible. The biological treatment systems are unable to handle “shock loads” efficiently.
What is a bioreactor made of?
The bioreactors are commonly made of stainless steel, usually cylindrical in shape and range in size from liters to cubic meters. The bioreactors are classified as batch, plug, or continuous flow reactors (e.g., continuous stirred-tank bioreactor).
When was vermifiltration introduced?
The introduction of earthworms to the filtration systems, termed vermifiltration systems, was advocated by José Toha in 1992 [ 21 ]. Vermifilter is widely used to treat wastewater, and appeared to have high treatment efficiency, including synchronous stabilization of wastewater and sludge [ 22, 23, 24 ].
What is the process of aeration?
Aeration has been used to remove trace organic volatile compounds (VOCs) in water. It has also been employed to transfer a substance, such as oxygen, from air or a gas phase into water in a process called “gas adsor ption” or “oxidation”, i.e., to oxidize iron and/or manganese.
What are some examples of bioremediation?
Example of bioremediation: fish bone char has been shown to bioremediate small amounts of cadmium, copper, and zinc. The bioremediation of wastewater can be achieved by autotrophs or heterotrophs.
Does temperature affect substrate removal?
The higher temperatures increase the biological activity and metabolism, which result in increasing the substrate removal rate. However, the increased metabolism at the higher temperatures may lead to problems of oxygen limitations. 4.2. Bacterial kinetics.
Is biological treatment secondary or tertiary?
The recent developments elucidate that subsequent to the physical treatment processes (the primary treatment) the biological treatment processes come in turn as secondary treatment and precede the chemical treatment processes, which constitute the tertiary treatment.
What is biological wastewater treatment?
Biological wastewater treatment is an effective way of breaking down and eliminating organic waste, typical of the waste products produced in the food and drink, chemical, oil and gas industries. Biological treatment is complex and has many different aspects to it.
How are flocs removed from wastewater?
Flocs can then be removed from the wastewater through the sedimentation process. The disadvantage of activated sludge processes is that they require a lot of space, and can produce large amounts of sludge. On the plus side, they are cheap to build and maintain when compared with other options.
What is a biological filter?
Biological trickling filters. Biological trickling filters can be used to remove organic contamination from either wastewater or air. The air or water is passed through some type of medium which will allow biofilm to collect on its surface. This biofilm, composed of both anaerobic and aerobic bacteria, will break down organic contamination.
How does wastewater get clumps?
These then break the organic material down to form biological solids which form clumps known as flocs. Flocs can then be removed from the wastewater through the sedimentation process.
What is an MBR tank?
A typical MBR will have both aerobic and anaerobic treatment tanks, a system for aeration, a tank with a membrane, and an ultrafiltration membrane. Although effective, the downside of a MBR system is that it is expensive to build initially, and also involves higher operating and maintenance costs.
What is activated sludge?
Activated sludge is a system that has been around since the start of the 20 th century. It’s the most common biological treatment used in large utility type water treatment plants but also has a place in other industrial settings. Wastewater first flows into an aeration tank, where oxygen is pumped into the water to feed ...
What is the biological oxygen demand?
Biological Oxygen Demand, or BOD, is the name of the measurement used to quantify the amount of dissolved oxygen needed by the anaerobic bacteria in the system to break down organic matter. A high level of BOD means that there is a high level of biodegradable material in the water.