Explore topic-wise MCQs in Environmental Engineering.

This section includes 18 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following has minimum hydraulic retention time?

A. Conventional process
B. Extended process
C. Modified aeration process
D. Complete mix process
Answer» D. Complete mix process
Discussion
2.

_________ is the time at which sewage is detained in the aeration tank.

A. Average time
B. Detention time
C. Aeration period
D. Reaeration period
Answer» D. Reaeration period
Discussion
3.

BOD of sewage is dependent on food to microorganism ratio.

A. True
B. False
Answer» B. False
Discussion
4.

The maximum BOD removal efficiency of the Step aeration process of the activated sludge system is ___________

A. 92%
B. 80%
C. 99%
D. 78%
Answer» B. 80%
Discussion
5.

The design value of food to microorganism ratio in the tapered aeration sludge process is ___________

A. 0.1
B. 0.2
C. 0.4
D. 0.8
Answer» D. 0.8
Discussion
6.

_________ is defined as a volume in ml occupied by 1 gram of solid in the mixed liquor after 30 minutes of settling.

A. BOD loading
B. Suspended solid volume
C. Sludge volume index
D. Organic loading
Answer» D. Organic loading
Discussion
7.

The organic loading in an activated sludge plant is defined as ___________

A. Mass of BOD per day/Volume of the aeration tank
B. Volume of aeration tank/Mass of BOD per day
C. The mass of BOD per day/Volume of secondary clarifier
D. Aeration period * Volume of aeration tank
Answer» B. Volume of aeration tank/Mass of BOD per day
Discussion
8.

The maximum aeration period for a conventional activated sludge system is ___________

A. 2 hours
B. 3 hours
C. 4 hours
D. 6 hours
Answer» E.
Discussion
9.

Which of the following has minimum hydraulic retention time?$

A. Conventional process
B. Extended process
C. Modified aeration process
D. Complete mix process
Answer» D. Complete mix process
Discussion
10.

_________ is the time at which sewage is detained in the aeration tank.$

A. Average time
B. Detention time
C. Aeration period
D. Reaeration period
Answer» D. Reaeration period
Discussion
11.

The maximum BOD removal efficiency of the Step aeration process of the activated sludge system i?

A. 92%
B. 80%
C. 99%
D. 78%
Answer» B. 80%
Discussion
12.

Which of the following sludge process has maximum aeration period?

A. Conventional process
B. Extended process
C. Step aeration process
D. Tapered aeration
Answer» C. Step aeration process
Discussion
13.

The design value of food to microorganism ratio in the tapered aeration sludge process is

A. 0.1
B. 0.2
C. 0.4
D. 0.8
Answer» D. 0.8
Discussion
14.

_________ is defined as a volume in ml occupied by 1gram of solid in the mixed liquor after 30 minutes of settling.

A. BOD loading
B. Suspended solid volume
C. Sludge volume index
D. Organic loading
Answer» D. Organic loading
Discussion
15.

The organic loading in an activated sludge plant is defined as

A. Mass of BOD per day/Volume of the aeration tank
B. Volume of aeration tank/Mass of BOD per day
C. The mass of BOD per day/Volume of secondary clarifier
D. Aeration period * Volume of aeration tank
Answer» B. Volume of aeration tank/Mass of BOD per day
Discussion
16.

The maximum aeration period for a conventional activated sludge system is

A. 2 hours
B. 3 hours
C. 4 hours
D. 6 hours
Answer» E.
Discussion
17.

Which of the following activated sludge process has minimum food to microorganism ratio?

A. Extended aeration
B. Step aeration
C. Modified aeration
D. Conventional
Answer» B. Step aeration
Discussion
18.

Which of the following is the correct expression of the aeration period in hours?

A. V/Q
B. 24V/Q
C. V/24Q
D. Q/V
Answer» C. V/24Q
Discussion