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Question
The image given below represents a sewage treatment plant (STP). Identify A and B in the image.
The image given below represents a sewage treatment plant (STP). Identify A and B in the image.
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Solution
The correct option is C A - Filtration tank, B - Sedimentation tank
The large quantities of waste water that is generated every day in cities and towns is known as sewage. It contains human excreta, large amounts of organic matter (food waste) and pathogenic microbes. It is treated in sewage treatment plants (STPs) before it is discharged into natural water bodies in order to reduce pollution.
The first stage of treatment is called primary treatment. It involves the physical removal of particles from the sewage through filtration and sedimentation.
Filtration: The floating debris is removed by sequential filtration during which sewage is passed through more than one filter of varying pore sizes in series.
The filtration tank is marked as A in the image.
Sedimentation: The filtrate obtained from sequential filtration is allowed to stand undisturbed for a certain time. The heavier particles such as soil and small pebbles settle down under the effect of gravity and form the sediment which is referred to as primary sludge. The supernatant formed is called the effluent and it undergoes further secondary treatment.
The sedimentation tank is marked as B in the image.
Therefore, option c is correct.
A - Filtration tank, B - Sedimentation tank
After primary treatment, the effluent is passed into large aeration tanks for the secondary treatment of sewage. In the secondary treatment, the enzymatic digestion of the effluent takes place by living organisms like heterotrophic aerobic microbes (bacteria and fungi) and hence is called biological treatment.
The large quantities of waste water that is generated every day in cities and towns is known as sewage. It contains human excreta, large amounts of organic matter (food waste) and pathogenic microbes. It is treated in sewage treatment plants (STPs) before it is discharged into natural water bodies in order to reduce pollution.
The first stage of treatment is called primary treatment. It involves the physical removal of particles from the sewage through filtration and sedimentation.
Filtration: The floating debris is removed by sequential filtration during which sewage is passed through more than one filter of varying pore sizes in series.
The filtration tank is marked as A in the image.
Sedimentation: The filtrate obtained from sequential filtration is allowed to stand undisturbed for a certain time. The heavier particles such as soil and small pebbles settle down under the effect of gravity and form the sediment which is referred to as primary sludge. The supernatant formed is called the effluent and it undergoes further secondary treatment.
The sedimentation tank is marked as B in the image.
Therefore, option c is correct.
A - Filtration tank, B - Sedimentation tank
After primary treatment, the effluent is passed into large aeration tanks for the secondary treatment of sewage. In the secondary treatment, the enzymatic digestion of the effluent takes place by living organisms like heterotrophic aerobic microbes (bacteria and fungi) and hence is called biological treatment.
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