Full Answer
What is secondary settling in wastewater treatment?
Secondary treatment consists of a biological process and secondary settling is designed to substantially degrade the biological content of the sewage such as are derived from human waste, food waste, soaps and detergent. The majority of municipal and industrial wastewater plants treat the settled sewage liquor using aerobic biological processes.
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.
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 the final step in the secondary treatment process?
The final step in the secondary treatment stage is to settle out the biological floc or filter material in a secondary sedimentation tank (SST) or secondary clarifier and produce sewage water containing very low levels of organic material and suspended matter
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 mechanical process?
So, the correct answer is 'Biological process'
Which type of process are used in secondary treatment of water?
Secondary wastewater treatment processes use microorganisms to biologically remove contaminants from wastewater. Secondary biological processes can be aerobic or anaerobic, each process utilizing a different type of bacterial community.
Which process is mainly involved in the secondary treatment of typical wastewater treatment plant?
Secondary Wastewater Treatment Of the three filters, trickling filters are typically the most effective for small-batch wastewater treatment. Aeration is a long, but effective process that entails mixing wastewater with a solution of microorganisms.
What is the process of secondary 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.
Is secondary treatment a chemical process?
Secondary wastewater treatment may be accomplished by biological or chemical -physical methods. Activated sludge and trickling filters are two of the most common means of secondary treatment.
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.
Where is secondary treatment is done for sewage purification?
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.
Which is the secondary treatment of sewage water Mcq?
1. Sewage treatment plant is a part of secondary treatment.
What process does sewage treatment involves?
Answer: Sewage treatment involves three processes, namely physical, chemical and biological. They remove physical, chemical and biological contaminants present in the wastewater.
What is true about secondary sewage treatment?
Secondary sewage treatment is mainly a biological process. In secondary treatment primary effluent is passed into large aeration tanks, where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into floes.
What is done during second stage of primary treatment?
Answer: Secondary Wastewater treatment is the second stage of wastewater treatment. In primary treatment, suspended solids, colloidal particles, oil, and grease are removed. In secondary treatment, biological treatment is done on the wastewater to remove the organic matter present.
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 purpose of sewage treatment?
The purpose of the sewage treatment is to remove the solids present in the sewage. ROLE OF MICROORGANISMS. Microorganisms are unicellular microscopic living things. They multiply by binary division of cells within 10 to 20 minutes. They require oxygen for their respiration.
What is secondary treatment?
The secondary treatment is designed to remove soluble organics from the wastewater. Secondary treatment consists of a biological process and secondary settling is designed to substantially degrade the biological content of the sewage such as are derived from human waste, food waste, soaps and detergent.
What is activated sludge?
The activated sludge process (ASP) is an aerobic biological wastewater treatment process that uses microorganisms, including bacteria, fungi, and protozoa, to speed up decomposition of organic matter requiring oxygen for treatment.
What is the only thing to be provided for the respiration of aerobic organisms?
The organic solids present in the wastewater serve as food for the aerobic microorganisms. The only thing to be provided is the DO , which is essential for the respiration of the aerobic organisms.
What are the end products of anaerobic and aerobic processes?
Under aerobic conditions, if completely oxidized, organic matter is transformed into non-hazardous products. But an anaerobic process can produce methane (CH 4 ), which is explosive, and ammonia (NH 3) and hydrogen sulfide (H 2 S), which are toxic.
What are the two types of biological processes?
TYPES OF BIOLOGICAL PROCESSES. There are two types of biological treatment process; aerobic and anaerobic. Aerobic process means that oxygen is present for the microbes for respiration. Anaerobic process means that the process proceeds in the absence of DO.
What do aerobic bacteria use for respiration?
Aerobic bacteria use dissolved oxygen (DO) from the water bodies for their respiration. They oxidize organic matter under aerobic conditions. The end products of the decomposition are water, CO 2 and Cell tissues. Anaerobic bacteria use oxygen derived from chemical substances for their respiration.
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.
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;
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:
