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प्रश्न
Explain the steps involved in preliminary treatment of sewage.
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उत्तर
- Screening: Sewage and waste water contain plenty of suspended, floating materials, coarse, and solid particles, along with dissolved substances. The suspended objects are filtered and removed. This is done in screening chambers. The sewage is passed through screens or net in the chambers. Larger suspended or floating objects are held in the screening chambers. These have to be removed before the biological treatment.
- Grit Chamber: After screening, the filtered sewage is then passed into a series of grit chambers. These chambers contain large stones (pebbles) and brick-ballast. Coarse particles settle down by gravity. Thus, passage of filtered sewage removes much of the coarse particulate matter.
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संबंधित प्रश्न
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?
Why is this sewage water treatment essential?
Small part of activated sludge is passed back into primary sedimentation tank.
If the above statement is correct then rewrite as it is and in case it is incorrect then reframe it.
The purpose of biological treatment of waste water is to ______.
Due to which of the following reason/s sewage water cannot be discharged directly into river?
Which of the following occurs during tertiary treatment?
In the process of biogas production which of the following anaerobic bacteria are used?
Study the following statements regarding tertiary treatment of sewage and choose the correct option.
i. It produces methane gas.
ii. The effluents formed from these plants undergo chlorination.
iii. BOD is significantly increased at this step.
iv. It includes screening and passage of effluent through grit chamber.
What would happen if oxygen availability to activated sludge flocs is reduced?
What would happen if a large volume of untreated sewage is discharged into a river?
