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प्रश्न
Answer the following question.
Secondary treatment of the sewage is also called Biological treatment. Justify this statement and explain the process.
उत्तर
Secondary treatment or Biological treatment :
- Primary effluent is passed into large aeration tanks with constant mechanical agitation and air supply.
- Useful aerobic microbes grow rapidly and form flocs.
- Flocs are masses of bacteria and consume organic matter and thus reduce the biochemical oxygen demand (BOD).
- When BOD of sewage has reduced, the effluent is passed into the Settling tank.
- Here, the bacterial flocs settle and sediment is called activated sludge.
- A small part of the sludge is used as an inoculum in the aeration tank and the remaining part is passed into large tanks called anaerobic sludge digesters.
- In the digesters, heterotrophic microbes anaerobically digest bacteria and fungi in sludge producing a mixture of gases such as methane, H2S, CO2which forms the biogas.
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संबंधित प्रश्न
Why is this sewage water treatment essential?
Small part of activated sludge is passed back into ______ and major part is pumped into large tanks called ______.
Identify the INCORRECT statement with respect to sewage treatment.
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.
In the process of sewage treatment, the activated sludge is digested by ______
In a sewage treatment plant, all of the following processes belong to secondary treatment except:
What would happen if oxygen availability to activated sludge flocs is reduced?
Why do we prefer to call secondary waste water treatment as biological treatment?
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".
The aeration tank of a sewage treatment plant is not functioning properly. Explain in detail the impact of this on the treatment of sewage and BOD of the effluent.
