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प्रश्न
Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.
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उत्तर
After the primary treatment, the primary effluent is taken for secondary treatment where it is passed into large aeration tanks and is constantly agitated and air is pumped into it. This leads to the vigorous growth of useful aerobic microbes into flocs. Flocs are masses of bacteria associated with fungal filaments to form mesh like structures. These microbes in the flocs consume the major part of the organic matter in the effluent and reduces the BOD (biological oxygen demand) of the effluent. Less BOD means that the waste water is less polluted.
After this, the effluent is passed into a settling tank where the flocs are allowed to settle and this sediment is called activated sludge. A small part of the activated sludge is pumped back to serve as the inoculum. Inoculum is the small amount of a material containing microbes that can start a new culture. This way same microbial culture is recycled and reused to start a new culture for the treatment.
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संबंधित प्रश्न
Explain the different steps involved during primary treatment phase of sewage.
Explain the process of secondary treatment given to the primary effluent up to the point it shows significant change in the level of biological oxygen demand (BOD) it.
Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each, assuming the river water is relatively clean?
One of the free-living anaerobic nitrogen-fixer is _________.
After which of the following process effluents from anaerobic sludge digesters are released in natural water bodies?
Which of the following occurs during secondary treatment?
During tertiary treatment, the bacterial floes sediment in the sedimentation tank, this sediment is called ____________.
Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste waters rich in organic matter. Discuss.
Given below is the flowchart of sewage treatment. Identify A, B, C, D and E and select the correct option.
Removal of suspended, floating, coarse and solid particles in sewage treatment is called ______.
