Advertisements
Advertisements
Question
Explain the role of microbes in sewage treatment.
Advertisements
Solution
Microbes play a significant role during secondary and tertiary sewage treatment.
- During secondary treatment, primary effluent is continuously agitated in a large tank due to which vigorous growth of useful aerobic microbes into flocs takes place. These microbes consume major part of the organic matter in the effluent as they grow. Due to this, BOD of the effluent is significantly reduced.
- During tertiary treatment, bacterial flocs are allowed to sediment. Small part of it is passed back into the aeration tank and a large part is pumped into large tanks called anaerobic sludge digesters. These anaerobic bacteria digest the bacteria and fungi in sludge.
- Thus, use of microbes in sewage treatment helps to remove organic matter from waste water before it is discharged in water bodies like rivers.
APPEARS IN
RELATED QUESTIONS
Distinguish between the roles of flocs and anaerobic sludge digesters in sewage treatments.
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?
Removal of large pieces of floating debris, oily substances, etc. during sewage treatment is called _______________.
The purpose of biological treatment of waste water is to ______.
After which of the following process effluents from anaerobic sludge digesters are released in natural water bodies?
Into which of the following the sewage water is pumped after preliminary treatment?
Identify the type of microorganisms involved in floe formation during sewage treatment.
______ refers to the organic matter which settles down after physical treatment of sewage.
During tertiary treatment, the bacterial floes sediment in the sedimentation tank, this sediment is called ____________.
Activated sludge should have the ability to settle quickly so that it can ______.
