Full Answer
What is secondary treatment of wastewater?
Secondary treatment of wastewater removes the dissolved organic matter that escapes primary treatment and eliminates a higher percentage of suspended solids. In this blog, I will walk you through various biological methods used in the secondary treatment of wastewater.
What is the purpose of sewage treatment?
The purpose of the sewage treatment is to remove the solids present in the sewage. Microorganisms are unicellular microscopic living things. They multiply by binary division of cells within 10 to 20 minutes. They require oxygen for their respiration. They decompose the organic matter and convert them into cells.
What are the available options in the biological treatment processes of sewage?
Available options in the biological treatment processes of domestic sewage options are The first two methods are Conventional treatment processes, the next four methods are Low cost methods and the last two methods are emerging technologies. Trickling filters are intended to treat particularly strong or variable organic loads.
What is Stage 2 of the wastewater treatment process?
STAGE TWO: PRIMARY TREATMENT It involves the separation of solid, organic matter (or human waste) from the wastewater. It is done by putting the wastewater into large settlement tanks for the solids to sink to the bottom. The settled solids are called sludge.
Which type of process is secondary sewage treatment?
Secondary treatment involves the removal of biodegradable organic matter (BOD) and suspended solids (TSS) through the processes of aeration and filtration. Secondary treatment is typically characterized as producing a treated wastewater effluent with a BOD of 25 mg/L or less and TSS of 30 mg/L or less.
Is secondary sewage treatment a chemical process?
So, the correct answer is 'Biological process'
Which processes are involved in secondary waste treatment?
Secondary Wastewater Treatment TREATMENTActivated Sludge Process (ASP) / Extended Aeration System (EAS)Sequential Batch Reactor (SBR)Moving Bed Bio Film Reactor (MBBR)Membrane Bioreactor (MBR)
What is a secondary treatment system?
Secondary treatment system is a wastewater treatment system which produces treated wastewater of secondary standard, i.e. 20 mg/L of Biochemical Oxygen Demand (BOD), 30 mg/L of Total suspended solids (TSS) and 10 cfu/100 mL of Escherichia (E) coli.
Why is secondary treatment a biological process?
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 chemical treatment of sewage?
Specialized chemicals such as chlorine, hydrogen peroxide, sodium chlorite, and sodium hypochlorite (bleach) act as agents that disinfect, sanitize, and assist in the purification of wastewater at treatment facilities.
Which of the following treatment is considered as secondary treatment *?
Secondary treatment is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. The aim is to achieve a certain degree of effluent quality in a sewage treatment plant suitable for the intended disposal or reuse option.
What is secondary stage in waste water treatment?
Secondary Treatment The secondary stage of treatment removes about 85 percent of the organic matter in sewage by making use of the bacteria in it. The principal secondary treatment techniques used in secondary treatment are the trickling filter and the activated sludge process.
Which is the secondary treatment of sewage water Mcq?
1. Sewage treatment plant is a part of secondary treatment.
What is primary secondary and tertiary treatment of wastewater?
Wastewater is treated in 3 phases: primary (solid removal), secondary (bacterial decomposition), and tertiary (extra filtration).
What is secondary waste?
Secondary waste is waste generated from different sources and of different nature, i.e. waste generated in a process that is known as a waste treatment operation; it includes residual materials originating from recovery and disposal operations, such as incineration and composting residues.
Why is secondary treatment often needed for sewage?
Secondary treatment removes the soluble organic matter that escapes primary treatment. It also removes more of the suspended solids. Removal is usually accomplished by biological processes in which microbes consume the organic impurities as food, converting them into carbon dioxide, water, and energy…
Secondary Treatment Definition
Secondary treatment of wastewater is a process that follows the primary treatment of sewage.
Objectives of Secondary Treatment
The objectives of secondary treatment are to remove the remaining suspended solids, BOD, and COD from the wastewater. It is done to reduce the primary clarifier load and improve the quality of the effluent discharged from the treatment plant.
What are the Stages of Wastewater Treatment?
The stages of wastewater treatment are collection, pre-treatment, primary treatment, secondary treatment, tertiary treatment, disposal, and reuse.
What is The Secondary Treatment of Wastewater?
This article will tell you about the second stage in the wastewater treatment process.
How Does Secondary Treatment Work
Secondary treatment is treating wastewater in a municipal water system that removes most contaminants from wastewater by reducing their levels to acceptably low levels.
What are The Alternative Types of Secondary Biological Processes?
There are a few different types of alternative secondary biological processes, and these include aerobic and anaerobic processes.
Conclusion
The secondary wastewater treatment process is more complicated than the primary wastewater treatment process. It is necessary to remove the remaining pollutants from the wastewater. The method includes various other activities that can remove the remaining impurities.
Aerobic Processes
Aerobic secondary treatment of wastewater occurs when various types of electron acceptors are present in the medium then the bacterial cells will utilize the one that produces the highest quantity of energy. Thus aerobic processes will utilize oxygen first.
Anoxic Processes
If the nitrates are present then the microorganisms which are capable of utilizing nitrogen will prevail. during respiration, they will convert nitrate to nitrogen gas (Denitrification) and the processes are collectively called anoxic processes.
Anaerobic Processes
When nitrates are consumed then anaerobic processes start to prevail and other nutrients such as sulfates are utilized. During this process, the sulfates will be converted to sulfites and Carbon-d i-oxide to methane.
Suspended Growth Process
In this growth process, the microorganism which is responsible for the conversion of waste organic matter is maintained into suspension of the liquid phase. Aerobic suspended growth processes include Activated Sludge Processes, Aerated Lagoons, and Sequential Batch Reactors.
Attached Growth Processes
In attached growth processes the microorganisms are attached to the surfaces (such as stones, inert materials) or are self immobilized on flocs or granules in the system. Aerobic Attached Growth Processes include Trickling Filters, Roughing Filters, Rotating Biological Contractors, and Packed Bed Reactors.
What is the treatment of sewage?
The treatment of sewage is one of the important measures, which aims in the removal of BOD, phosphorous, nitrogen, solids and bacteria. The composition of sewage is complex, and it differs depending upon the sources, the type of treatment or lack of it. The process of treating sewage is broadly classified as primary;
What is secondary treatment of waste?
Secondary treatment of waste involves the biological degradation of organic material by micro-organisms under controlled conditions. The usual method is to bring about the biological oxidation of the organic material under aerobic conditions, in which the waste is aerated to supply oxygen for the micro-organisms.
Why is primary sludge a problem?
ADVERTISEMENTS: Primary sludge is a problem because it is bulky and must be removed. It also contains 94 to 99 per cent water. In some cases, sludge is dried in beds with some water removed by filtration.
What is primary treatment?
Primary treatment consists of removing floating and suspended solids by mechanical means. More than half of the suspended solids can be removed by primary treatment as shown in Figure 8.4.
What are the methods of tertiary treatment?
The number of methods used for tertiary treatment is: (iii) Chemical oxidation. (v) Oxidation ponds. However, there is a growing need for advanced procedures that will provide a product capable of being reused for various purposes.
How is sand removed from water?
Sand and other coarse material is removed by grit chambers . After screening and removal of grit, the waste water is run directly into settling or sedimentation tanks, the process by which the suspended solids are removed by gravitational setting. ADVERTISEMENTS:
What is Secondary or Biological treatment for wastewater?
Secondary or Biological treatments for wastewater remove organic pollutants using bacteria. In other words, bacteria consume organic matter as food and convert them to carbon dioxide, water, and energy towards their growth and reproduction.
Types of Secondary or Biological Treatment Methods
The three most commonly used aerobic secondary treatment procedures for wastewater are listed below:
Trickling Filter
A trickling filter is an aerobic secondary wastewater treatment system that uses a biofilm of microbes attached to the filter media to remove organic pollutants. These systems are also known as attached-growth processes in contrast to the suspended growth systems wherein microbes are suspended in the effluent.
Oxidation Ponds
Oxidation Ponds are man-made ponds that treat wastewater through the combined action of sunlight, microbes and oxygen to reduce the organic content and pathogens. It refers to a stabilisation pond that uses microbes to stabilise residential, commercial, and industrial wastes.
Activated Sludge Process
The Activated Sludge process employs aerobic microorganisms that can digest organic substances in sewage. Also, they have the ability to cluster together via flocculation. The flocculated particles settle out as sludge. As a result, the liquid coming out is relatively free of suspended solids and organic matter.
Conclusion
We took a short trip through various secondary treatment methods for wastewater namely trickling filter, oxidation pond, activated sludge process and anaerobic sludge blanket reactors. The sludge coming out of these secondary wastewater treatment plants undergoes dewatering and digestion.
What is the most effective method of secondary treatment of wastewater?
This method of secondary treatment of wastewater employs sand filters, contact filters, or trickling filters to ensure that additional sediment is removed from wastewater. Of the three filters, trickling filters are typically the most effective for small-batch wastewater treatment.
What is primary treatment of wastewater?
Primary treatment of wastewater involves sedimentation of solid waste within the water. This is done after filtering out larger contaminants within the water. Wastewater is passed through several tanks and filters that separate water from contaminants.
What is the third step in wastewater management?
This third and last step in the basic wastewater management system is mostly comprised of removing phosphates and nitrates from the water supply. Substances like activates carbon and sand are among the most commonly used materials that assist in this process.
How long does it take for a wastewater solution to be aerated?
The resulting mixture is then aerated for up to 30 hours at a time to ensure results.
What is the first stage of wastewater treatment?
Screening is the first stage of the wastewater treatment process. Screening removes large objects like diapers, nappies, sanitary items, cotton buds, face wipes, and even broken bottles, bottle tops, plastics, and rags that may block or damage equipment.
How is wastewater treated?
It is done by putting the wastewater into large settlement tanks for the solids to sink to the bottom. The settled solids are called sludge. At the bottom of these circular tanks, large scrappers continuously scrape the floor of the tank and push the sludge towards the center, where it is pumped away for further treatment. The rest of the water is moved to Secondary treatment.
Why is air pumped into sludge scraping water?
These are called aeration lanes. Air is pumped into the water to encourage bacteria to break down the tiny bits of sludge that escaped the sludge scraping process.
Where does liquid waste go?
Wastewater (liquid waste) from flushing the toilet, bathing, washing sinks, and general cleaning goes down the drain and into a pipe, which joins a larger sewer pipe under the road. The sewer pipe goes on to connect to a different sewer pipe that leads to the treatment center.
