Explain the different steps involved in water treatment plant with the help of diagram for each step.
pls explain the answer
Answers
Explanation:
Primary treatment or physical treatment
It is the physical removal of large and small particles from sewage.
First, the floating debris is removed by sequential filtration by passing through wire mesh screens.
Then, the grit (soil and small pebbles) are removed by sedimentation in settling tanks. The sediment is called primary sludge and the supernatant is the effluent.
The effluent is taken for secondary treatment.
(ii) 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.
The growing microbes consume organic matter and thus reduce the biochemical oxygen demand (BOD).
When BOD of sewage has reduced, the effluent is passed into settling tank.
Here, the bacterial flocs settle and the 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.
Primary treatment or physical treatment
It is the physical removal of large and small particles from sewage.
First, the floating debris is removed by sequential filtration by passing through wire mesh screens.
Then, the grit (soil and small pebbles) are removed by sedimentation in settling tanks. The sediment is called primary sludge and the supernatant is the effluent.
The effluent is taken for secondary treatment.
(ii) 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.
The growing microbes consume organic matter and thus reduce the biochemical oxygen demand (BOD).
When BOD of sewage has reduced, the effluent is passed into settling tank.
Here, the bacterial flocs settle and the 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