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Activated Sludge I

Total questions: 24

Worksheet time: 12mins

Name
Class
Date
1.

Activated sludge process degrade organics and _________

a)

Improve nutrients

b)

Remove nutrients

c)

Remove odour

d)

Remove taste

2.

What is required to keep the activated sludge suspended?

a)

Carbon-dioxide

b)

Nitrogen

c)

Oxygen

d)

Ammonia

3.

What does the bacterium use to grow?

a)

Oxygen

b)

Organic pollutants

c)

Water

d)

Carbon-dioxide

4.

Activated sludge process can be used for treating all types of wastewater.

a)

True

b)

False

5.

________ combines aeration basin and secondary clarifier into single unit.

a)

Primary clarifier

b)

Aerobic unit

c)

Sequential batch reactor

d)

Secondary clarifier

6.

What does SBR stand for?

a)

Secondary batch reactor

b)

Sequential biological reactor

c)

Secondary biological reactor

d)

Sequential batch reactor

7.

SBR operates as ________ process.

a)

Batch

b)

Continuous

c)

Semi-continuous

d)

Discontinuous

8.

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

9.

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

a)

Flocculation

b)

Aeration

c)

Sedimentation

d)

Clarification

10.

Why is the sludge aerated?

a)

To avoid bacterial growth

b)

To increase bacterial growth

c)

To maintain pH

d)

To maintain temperature

11.

________ is treated in activated sludge reactor.

a)

Pre-treated sludge

b)

Treated sludge

c)

Macronutrients

d)

Micro-organisms

12.

After the treatment, the BOD demand ______

a)

Remains constant

b)

Decreases

c)

Increases

d)

Alters

13.

Which is the next reactor after activated sludge reactor in the treatment process?

a)

Flocculation unit

b)

Aeration unit

c)

Clarifier

d)

Disinfection unit

14.

Where is the sludge at the bottom of the clarifier processed to?

a)

Settling unit

b)

Aerator

c)

Flocculation unit

d)

Disinfection unit

15.

Which of these is not an alternative to activated sludge treatment systems?

a)

Stabilization ponds

b)

Rotating biological reactors

c)

Trickling filter

d)

Screening units

16.

An activated sludge system consists of two components, an aerator and ________

a)

Screening units

b)

Disinfection unit

c)

Flocculation unit

d)

Clarifier

17.

How is air pumped in the aerator unit?

a)

Bubbled from bottom

b)

Sides

c)

Bubbled from top

d)

Sprayed

18.

Which are the three ingredients in activated sludge systems?

a)

Cells, sewage and oxygen

b)

Cells, sewage and nitrogen

c)

Solids, sewage and oxygen

d)

Solids, water and oxygen

19.

The organisms feed on _____ in aeration tanks.

a)

Water

b)

Air

c)

Sludge particles

d)

Bacteria

20.

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

21.

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

a)

Extended aeration

b)

Step aeration

c)

Modified aeration

d)

Conventional

22.

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

23.

Which of the following sludge process has maximum aeration period?

a)

Conventional process

b)

Extended process

c)

Step aeration process

d)

Tapered aeration

24.

Activated sludge process uses micro-organisms to degrade organics from wastewater

a)

True

b)

False