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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 function of “anaerobic sludge digester” in a sewage treatment plant.
Distinguish between the roles of flocs and anaerobic sludge digesters in sewage treatments.
Explain the process of sewage water treatment before it can be discharged into natural water bodies.
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?
Into which of the following the sewage water is pumped after preliminary treatment?
After which of the following treatment BOD of the effluent is significantly reduced?
The primary treatment of waste water involves the removal of ______.
What is the group of bacteria found in both the rumen of cattle and shidge of sewage treatment?
Given below is the flowchart of sewage treatment. Identify A, B, C, D and E and select the correct option.
Biochemical Oxygen Demand (BOD) may not be good index for pollution for water bodies receiving effluents from ______.
