Question No:1

In context of secondary treatment of sewage, ‘flocs’ is associated with which microbes?

[A] Bacteria and algae
[B] Algae and fungus
[C] Fungi and bacteria
[D] Fungi and lichen



Question No:2

What is BOD?

[A] Bacterial Oxygen Demand
[B] Biological Organic Debris
[C] Biochemical Organic Demand
[D] Biochemical Oxygen Demand



Question No:3

The ‘floes’ present in large aeration tanks causes ______ in BOD.

[A] decrease
[B] increases
[C] no change
[D] Either (a) or (b)



Question No:4

BOD can be defined as:

[A] Amount of CO₂ consumed if all the inorganic matter in one litre of water is oxidized by bacteria.
[B] Amount of O₂ consumed if all the organic matter in one decilitre of water is reduced by bacteria.
[C] Amount of O₂ consumed if all the organic matter in one litre of water is oxidized by bacteria.
[D] Amount of O₂ consumed if all the inorganic matter in one litre of water is oxidized by bacteria.



Question No:5

BOD is the measure of ______ in water.

[A] organic matter
[B] inorganic matter
[C] bacterial load
[D] toxicity



Question No:6

BOD ______ polluting potential of waste water.

[A] is not proportional to
[B] is directly proportional to
[C] is inversely proportional to
[D] None of the above



Question No:7

Once BOD from the sewage is reduced significantly, the ‘floes’ are allowed to sediment and it is known as ______.

[A] Primary Sludge
[B] Secondary Sludge
[C] Activated Sludge
[D] Inactivated Sludge



Question No:8

Assertion (A): A small part of activated sludge is pumped back into aeration tank.
Reason (R): It serves as inoculum.

[A] A is true but R is false.
[B] A is true and R is correct explanation for A.
[C] A is false but R is true.
[D] Both A and R is false.



Question No:9

The remaining major part of activated sludge is pumped into large tanks called _____

[A] Aerobic fermenters
[B] Anaerobic fermenters
[C] Aerobic Sludge digesters
[D] Anaerobic Sludge digesters



Question No:10

In an anaerobic sludge digester, anaerobically digesting bacteria digest which microbes?

[A] Fungi
[B] Bacteria
[C] Algae
[D] Both (a) and (b)



Question No:11

In an anaerobic sludge digester, during the digestion process, mixture of gases like ____ are produced.

[A] CH₄, H₂ O, O₂
[B] C₂ H₆H₂S, CO₂
[C] CH₄, H₂O₂, CO₂
[D] CH₄, H₂S, CO₂



Question No:12

The gases that evolve from anaerobic sludge digester constitute ______

[A] Natural gas
[B] Biogas
[C] Water gas
[D] None of the above



Question No:13

After secondary treatment, the effluent is released into:

[A] Digester tank
[B] Filtration Unit
[C] Water bodies
[D] Chemical treatment unit



Question No:14

Which ministry has initiated Ganga Action Plan and Yamuna Action Plan?

[A] Ministry of Chemicals and Fertilizers
[B] Ministry of Health and Family Welfare
[C] Ministry of Community Health and Diseases
[D] Ministry of Environment and Forest



Question No:15

Which gas is the main constituent of biogas?

[A] H₂ S
[B] CH₄
[C] C₂ H₆
[D] C₃ H₈