Deck 7: Grit Chambers and Activated Sludge Processes

Question 1

Grit chamber is similar to which of the following?

A)Screening unit
B)Sedimentation tank
C)Coagulation tank
D)Sand bed

Answer 1

Sedimentation tank

Question 2

What is the specific gravity of settleable particles in the grit chamber?

A)2.98
B)2.56
C)2.65
D)2.89

Answer 2

2.65

Question 3

Stoke's law holds good for Reynolds's number ______

A)Less than 1
B)Equal to 1
C)Greater than 1
D)Nearer to 1

Answer 3

Less than 1

Question 4

What is the horizontal velocity considered for grit chamber?

A)0.25-0.4m/sec
B)0.6-0.9 m/sec
C)1-2 m/sec
D)3-4m/sec

Question 5

What is the detention time considered for aerated grit chamber?

A)5-6 mins
B)2-5 mins
C)1-2 mins
D)3-4 mins

Question 6

Which of these is not a grit removal equipment installed in the aerated grit chamber?

A)Screw conveyers
B)Tubular conveyers
C)Jet pumps
D)Communitors

Question 7

What is the amount of air supplied for these grit chambers?

A)1-2 m³/m.min
B)0.2-0.5 m³/m.min
C)0.5-0.8 m³/m.min
D)0.8-1 m³/m.min

Question 8

At what depth are the air diffusers placed in the grit chamber?

A)0.6-0.9 m
B)1-2 m
C)0.1-0.4m
D)0.45-0.6 m

Question 9

What is the amount of grit quantities captured by the aerated grit chamber?

A)0.004-0.20 m3/103.m³
B)0.25 m3/103.m³
C)<0.004 m3/103.m³
D)0.5 m3/103.m³

Question 10

Usually while designing what is the range of the width of the aerated grit chamber assumed?

A)0.5-2 m
B)8-10 m
C)2.5-7.0m
D)12m

Question 11

Usually while designing what is the range of length of the aerated grit chamber assumed?

A)7.5-20
B)4-6 m
C)25 m
D)50 m

Question 12

Usually while designing what is the range of depth of the aerated grit chamber assumed?

A)0.5-2 m
B)8-10 m
C)2-5 m
D)12 m

Question 13

Aerated grit chambers are usually designed to remove particles in which range of size?

A)0.1mm diameter
B)0.35 mm diameter
C)0.21 mm diameter
D)0.41 mm diameter

Question 14

Activated sludge process degrade organics and _________

A)Improve nutrients
B)Remove nutrients
C)Remove odour
D)Remove taste

Question 15

What is required to keep the activated sludge suspended?

A)Carbon-dioxide
B)Nitrogen
C)Oxygen
D)Ammonia

Question 16

What does the bacterium use to grow?

A)Oxygen
B)Organic pollutants
C)Water
D)Carbon-dioxide

Question 17

________ combines aeration basin and secondary clarifier into single unit.

A)Primary clarifier
B)Aerobic unit
C)Sequential batch reactor
D)Secondary clarifier

Question 18

What does SBR stand for?

A)Secondary batch reactor
B)Sequential biological reactor
C)Secondary biological reactor
D)Sequential batch reactor

Question 19

SBR operates as ________ process.

A)Batch
B)Continuous
C)Semi-continuous
D)Discontinuous

Question 20

When the aeration system shuts off, the basin begins to perform as a ______

A)Primary clarifier
B)Secondary clarifier
C)Anaerobic unit
D)Aeration unit

Question 21

_______ provides the dual purpose of providing DO and mixing of the mixed liquor and wastewater.

A)Flocculation
B)Aeration
C)Sedimentation
D)Clarification

Question 22

Ion-exchange resin is ____________

A)Linear
B)Low molecular weight
C)Organic polymer with porous structure
D)Soluble

Question 23

Which of the following ion get released from the cation exchange column?

A)H+
B)Na+
C)K+
D)Ca+2

Question 24

Which of the following ion get released from the anion exchange column?

A)CO₃-2
B)OH-
C)Cl-
D)SO₄-2

Question 25

Ion-free water coming out from the exchanger is known as ____________

A)Potable water
B)Disinfected water
C)Coagulated water
D)Demineralised water