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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
Answer the following question.
What are 'flocs', formed during secondary treatment of sewage?
Why is this sewage water treatment essential?
Which of the following is/are found in discharge from industrial waste?
Which of the following occurs during secondary treatment?
Wastewater treatment generates a large quantity of sludge, which can be treated by ______.
BOD of waste water is estimated by measuring the amount of ______.
Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste waters rich in organic matter. Discuss.
Study the given diagram of the Sewage Treatment Plant (S.T.P.) and answer the question that follows:


- Which one of the two 'S.T.P.' (A) or (B) will be more effective in treating the human excreta in municipal waste?
- Write the steps followed in carrying the treatment of the sewage in step (Z), once the BOD of sewage is reduced significantly till it is passed on to the "anaerobic sludge digesters".
Given below is the flowchart of sewage treatment. Identify A, B, C, D and E and select the correct option.

Which of the following statement is correct for Sewage Treatment Plants (STPs)?
