Water Treatment MCQs : This section focuses on the "Water Treatment". These Multiple Choice Questions (MCQs) should be practiced to improve the Water Treatment skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
The maximum desirable limit Bureau of Indian Standards (BIS) of lead in the drinking water is
A. 0.05 mg/l
B. 0.09 mg/l
C. 0.1 mg/l
D. 1.0 mg/l
Question 2
Zeolite softening process removes
A. only temporary hardness of water
B. only permanent hardness of water
C. both temporary and permanent hardness of water
D. the dissolved gases in permanent hard water
Question 3
Conventional tertiary treatment is
A. chemical coagulation and flocculation
B. filtration
C. sedimentation
D. None of the above
Question 4
The maximum desirable limit (BIS) of total hardness (as CaCo3) in drinking water is
A. 600 ppm
B. 300 ppm
C. 500 ppm
D. 1000 ppm
Question 5
The chemical oxygen demand (COD)measures the
A. amount of oxygen required for growth of microorganisms in water
B. amount of oxygen that would be removed from the water in order to oxidize pollution
C. amount of oxygen required to oxidize the calcium present in waste water
D. None of the above
Question 6
Hardness of water does not
A. have any bad effect in boiler
B. make cooking of foods difficult
C. make it unfit for drinking
D. cause difficulty in the washing of clothes with soaps
Question 7
Permanent hard water may be softened by passing it through
A. sodium silicate
B. sodium bicarbonate
C. sodium hexametaphosphate
D. sodium phosphate
Question 8
Zeolite used in zeolite softening process for the treatment of hard water gets exhausted after certain time of usage but can be regenerated by flushing it with
A. 10% calcium chloride solution
B. 10% magnesium sulfate solution
C. 10% magnesium chloride solution
D. 10% sodium chloride solution
Question 9
Temporary hardness of water is caused by the presence of
A. chlorides of calcium and magnesium
B. sulfates of calcium and magnesium
C. bicarbonates of calcium and magnesium
D. carbonates of sodium and potassium
Question 10
Secondary treatment uses __________ to consume wastes.
A. micro-organisms
B. chemicals
C. filtration
D. None of the above
Question 11
Application of quaternary ammonium compounds as sanitizing agents tends to
A. favor gram positive bacteria
B. decrease gram positive bacteria
C. increase the percentage of gram(-)ve rods on utensils
D. None of the above
Question 12
Permanent hardness of water is caused by the presence of
A. bicarbonates of calcium and magnesium
B. carbonates of sodium and potassium
C. chlorides and sulfates of calcium and magnesium
D. phosphates of sodium and potassium
Question 13
According to BIS the maximum permissible limit of dissolved solids in drinking water is
A. 1000 mg/l
B. 500 mg/l
C. 2000 mg/l
D. 1500 mg/l
Question 14
Acid used mostly for removal of milk stone is
A. phosphoric acid
B. nitric acid
C. gluconic acid
D. tartaric acid
Question 15
Which of the following chemical is sometime added in the process of coagulation and flocculation?
A. Aluminum sulphate
B. Aluminum oxide
C. Calcium chloride
D. None of the above
Question 16
Which of the following physical method is used as germicidal in modern time for the treatment of drinking water?
A. Chlorination
B. Treating with potassium permagnate
C. UV radiation
D. Treating with bleaching powder
Question 17
Sanitizer used specifically for vitreous enamel are
A. strong alkalis
B. strong acids
C. weak alkali with sodium silicate
D. None of the above
Question 18
The common methods used for disinfection in waste water treatment plants are
A. chlorination
B. UV light
C. Both A and B
D. Phenolic solvent
Question 19
Inhibitors are used along with sanitizer to
A. improve their action
B. to prevent corrosion
C. Both A and B
D. None of the above
Question 20
Sanitizers used for rubber made equipments are
A. strong acids
B. strong alkalis
C. combination of both
D. None of the above
Question 21
Which of the following substances are commonly used in a filter?
A. Charcoal
B. Sand
C. Both A and B
D. Aluminum chloride
Question 22
Biological oxidation processes usually referred as biological treatment, are the most common form of
A. primary treatment
B. secondary treatment
C. tertiary treatment
D. All of the above
Question 23
The maximum permissible limit (BIS) of turbidity in drinking water is
A. 5 NTU
B. 10 NTU
C. 15 NTU
D. 20 NTU
Question 24
Sedimentation is a physical process used in wastewater treatment to
A. remove particles that are less dense than water
B. remove particles that are more dense than water
C. remove the pertinacious material from the water
D. None of the above
Question 25
The ultimate source of water is
A. rivers and lakes
B. dew and forest
C. rain and snow
D. underground and surface
Question 26
Biological oxidation processes usually referred as biological treatment, are the most common form of
A. primary treatment
B. secondary treatment
C. tertiary treatment
D. all of these
Question 27
BOD stands for
A. biochemical oxygen demand
B. british oxygen demand
C. british oxygen depletion
D. biological oxygen depletion
Question 28
Both temporary and permanent hardness of water can be removed by
A. boiling
B. distillation
C. filtration
D. decantation
Question 29
Both temporary and permanent hardness of water can be removed on boiling water with
A. calcium hydroxide
B. sodium carbonate
C. calcium oxide
D. calcium carbonate
Question 30
Calgon is used for removal of
A. sodium carbonate
B. permanent hardness of water
C. potassium carbonate
D. none of these
Question 31
Coliform bacteria in water is an indication of the presence of
A. radioactive wastes
B. excess fertilizer
C. decaying animals and plants
D. human feces
Question 32
Conventional tertiary treatment is
A. chemical coagulation and flocculation
B. filtration
C. sedimentation
D. none of these
Question 33
From the following sanitizers which one comes under category of surface active agents?
A. Tetra phosphate
B. Teepol
C. Meta phosphate
D. None of these
Question 34
Inhibitors are used along with sanitizer to
A. improve their action
B. to prevent corrosion
C. both (a) and (b)
D. none of these
Question 35
Lagoons may be characterized as
A. anaerobic
B. facultative
C. aerated
D. all of these
Question 36
Permanent hardness of water may be removed by the addition of
A. lime
B. soda ash
C. potassium permagnate
D. sodium bicarbonate
Question 37
Sanitizer used specifically for vitreous enamel are
A. strong alkalis
B. strong acids
C. weak alkali with sodium silicate
D. none of these
Question 38
Sanitizers used for rubber made equipments are
A. strong acids
B. strong alkalis
C. combination of both
D. none of these
Question 39
Secondary treatment uses __________ to consume wastes.
A. micro-organisms
B. chemicals
C. filtration
D. none of these
Question 40
Temporary hardness of water may be removed by adding
A. calcium hydroxide
B. calcium carbonate
C. calcium chloride
D. sodium bicarbonate
Question 41
The activated sludge process consists of returning a portion of the clarifier
A. effluent water entering the reactor
B. influent water coming out of the reactor
C. influent water entering the reactor
D. effluent water coming out of the reactor
Question 42
The activated sludge process is sometime referred as
A. fluid bed biological oxidation system
B. fixed bed biological oxidation system
C. turning bed biological oxidation system
D. none of the above
Question 43
The common methods used for disinfection in waste water treatment plants are
A. chlorination
B. UV light
C. both (a) and (b)
D. Phenolic solvent
Question 44
The maximum desirable limit (BIS of mercury in the drinking water is
A. 0.05 mg/l
B. 0.9 mg/l
C. 0.1 mg/l
D. 0.001 mg/l
Question 45
The methods used for biological treatment are
A. lagoon
B. activated sludge process
C. oxidation ditches
D. all of these
Question 46
The purest form of naturally occurring water is
A. rain water
B. river water
C. pond water
D. well water
Question 47
The water being used in dairy industry should contain not more than
A. 5 proteolytic and/or lipolytic organisms per ml
B. 10 proteolytic and/or lipolytic organisms per ml
C. 15 proteolytic and/or lipolytic organisms per ml
D. 20 proteolytic and/or lipolytic organisms/ml
Question 48
When temporary hard water is boiled, one of the substances formed is
A. calcium bicarbonate
B. calcium sulfate
C. hydrogen chloride
D. carbon dioxide
Question 49
Which of the following chemical is sometime added in the process of coagulation and flocculation?
A. Aluminum sulphate
B. Aluminum oxide
C. Calcium chloride
D. None of these
Question 50
Which of the following substances are commonly used in a filter?
A. Charcoal
B. Sand
C. Both (a) and (b)
D. Aluminum chloride
Question 51
Zeolite softening process removes both temporary and permanent hardness of water. In this process the calcium and magnesium present in water are precipitated as
A. insoluble carbonates
B. insoluble zeolites
C. insoluble chlorides
D. insoluble sulfates
Question 52
Adsorption is an endothermic process.
A. True
B. False
Question 53
Chemical adsorption is also called as _____
A. Sorption
B. Chemisorption
C. Chemiption
D. Chemical sorption
Question 54
Chemical adsorption takes place at high temperature.
A. True
B. False
Question 55
Physical adsorption ________ with increase in temperature.
A. Decreases
B. Increases
C. Remains same
D. Fluctuates
Question 56
Physical adsorption is also called as _________
A. Adsorption
B. Absorption
C. Physisorption
D. Sorption
Question 57
What is the highest enthalpy of adsorption for chemical adsorption?
A. 100 KJ mol-1
B. 200 KJ mol-1
C. 300 KJ mol-1
D. 400 KJ mol-1
Question 58
What is the lowest enthalpy of adsorption for physical adsorption?
A. 5 KJ mol-1
B. 10 KJ mol-1
C. 15 KJ mol-1
D. 25 KJ mol-1
Question 59
Which force holds the molecules in physical adsorption?
A. Friction force
B. Van der waals force
C. Tension force
D. Nuclear force