Microbes In Human Welfare Question 24
Question: Consider the following statements about, secondary sewage treatment. Which of the statements given are correct?
(i) In secondary treatment useful aerobic microbes grow rapidly and form floes of bacterial and fungal filaments in a mesh- like structure. (ii) The growing microbes consume organic matter reducing the BOD after which the effluent is passed into settling tank. (iii) In settling tank, the bacterial floes settle and the sediment is called activated sludge. (iv) A small part of the sludge is used as an inoculum. The remaining part is passed into anaerobic sludge digesters. (v) On anaerobic digestion of bacteria and fungi mixture of gases such as, carbon dioxide, nitrogen and carbon monoxide are produced.
Options:
A) (i), (ii), (iii) and (iv)
B) (i), (iii), (iv) and (v)
C) (ii), (iii), (iv) and (v)
D) (i), (ii), (iii), (iv) and (v)
Show Answer
Answer:
Correct Answer: A
Solution:
[a] All statements are correct except (v).
Methane, hydrogen sulphide and C02 are the main gases produced in the digesters by the anaerobic digestion by heterotrophic bateria and fungi.
BETA
