Environmental Engineering Multiple Choice Questions on “Activated Carbon Treatment”.
1. Which of the following is used for the control of taste and odor in water?
a) Sedimentation
b) Coagulation
c) Filtration
d) Activated carbon
Answer: d
Clarification: Activated carbon is used for the control of taste and odor, which has resulted from the presence of dissolved gases.
2. Granular activated carbon has a surface area of ____________
a) 100-200m2/g
b) 500-1400m2/g
c) 400-600m2/g
d) 500-900m2/g
Answer: b
Clarification: Granular activated carbon has a surface area of 500-1400m2/g. Higher surface area is the prime consideration in adsorption.
3. _______ is produced by passing a carbonaceous material through a heating mechanism at high temperature.
a) Potassium per-manganate
b) Potassium dichromate
c) Activated carbon
d) Iodine
Answer: c
Clarification: Activated carbon is produced by passing a carbonaceous material through the heating mechanism at high temperature against air, steam, chlorine and flue gases.
4. Which of the following is a carbonaceous material?
a) Charcoal
b) Petroleum
c) Hydrogen sulfide
d) Sodium chloride
Answer: a
Clarification: Charcoal is a carbonaceous material. Various other carbonaceous materials are coke, paper, char and sawdust.
5. Which of the following is not a property of activated carbon?
a) It is impermeable
b) It has many carbon atoms with free valencies
c) It is available in granular as well as powder form
d) It has a prolonged suspension
Answer: a
Clarification: Activated carbon is very porous. It should have prolonged suspension, easily wettable and effective odor absorption capacity.
6. The thickness of the activated carbon filter bed is ____________
a) 10-20cm
b) 30-80cm
c) 75-100cm
d) 40-50cm
Answer: c
Clarification: The thickness of the activated carbon filter bed is between 75 to 100 cm which is supported on 35-50 cm thick graded gravel bed.
7. When activated carbon is applied at more than one point, then it is called ________
a) Dual treatment
b) Split treatment
c) Sludge treatment
d) Carbonaceous treatment
Answer: b
Clarification: The activated carbon in powder form can be applied to the water before, during or after coagulation at more than one point, which is called split treatment.
8. Activated carbon in powder form is applied in the mixing basin.
a) True
b) False
Answer: a
Clarification: Activated carbon in powder form can be applied in the mixing basin either alone or fixed with other chemicals like alum by means of a dry chemical feed machine.
9. Activated carbon can be applied to raw water ______ treatment process.
a) During
b) Ahead of
c) Before
d) After
Answer: b
Clarification: Activated carbon can be applied in various ways like ahead of the treatment process, in the mixing basin or after filtration. Its rate of application is high when the filter is washed.
10. The dose of activated carbon in powdered form is controlled by ____________
a) Chromatography
b) Distillation
c) Threshold odor test
d) MPN test
Answer: c
Clarification: The dose of activated carbon in powdered form is controlled by threshold odor test. For effective use, the dose must be adequate, thoroughly mixed and time of contact should be long.
11. What is the dose of copper sulfate required for the treatment of water?
a) 0.3-0.6ppm
b) 2-6ppm
c) 4-8ppm
d) 10-20ppm
Answer: a
Clarification: Copper sulfate is used for the removal of odor, taste and color from water and the dose required varies from 0.3 to 0.6ppm.
12. There are protozoa present in the water. Its name is Dinobryen. What is the dose of copper sulfate required to kill it?
a) 0.02ppm
b) 0.3ppm
c) 0.5ppm
d) 0.8ppm
Answer: b
Clarification: Dinobryen produces an aromatic, violet and fishy odor and the dose of copper sulfate required to kill it is 0.3ppm.