Water Treatment Questions and Answers

Multiple Choice Questions and Answers on Water Treatment 

Question 1 : Both temporary and permanent hardness of water can be removed by

  1. boiling
  2. distillation
  3. filtration
  4. decantation

Answer : 2

Question 2 : Coliform bacteria in water is an indication of the presence of

  1. radioactive wastes
  2. excess fertilizer
  3. decaying animals and plants
  4. human feces

Answer : 4

Question 3 : The activated sludge process is sometime referred as

  1. fluid bed biological oxidation system
  2. fixed bed biological oxidation system
  3. turning bed biological oxidation system
  4. none of the above

Answer : 1

Question 4 : BOD stands for

  1. biochemical oxygen demand
  2. british oxygen demand
  3. british oxygen depletion
  4. biological oxygen depletion

Answer : 1

Question 5 : When temporary hard water is boiled, one of the substances formed is

  1. calcium bicarbonate
  2. calcium sulfate
  3. hydrogen chloride
  4. carbon dioxide

Answer : 4

Question 6 : Zeolite softening process removes both temporary and permanent hardness of water. In this process the calcium and magnesium present in water are precipitated as

  1. insoluble carbonates
  2. insoluble zeolites
  3. insoluble chlorides
  4. insoluble sulfates

Answer : 2

Question 7 : The methods used for biological treatment are

  1. lagoon
  2. activated sludge process
  3. oxidation ditches
  4. all of these

Answer : 4

Question 8 : From the following sanitizers which one comes under category of surface active agents?

  1. Tetra phosphate
  2. Teepol
  3. Meta phosphate
  4. None of these

Answer : 2

Question 9 : The purest form of naturally occurring water is

  1. rain water
  2. river water
  3. pond water
  4. well water

Answer : 1

Question 10 : Calgon is used for removal of

  1. sodium carbonate
  2. permanent hardness of water
  3. potassium carbonate
  4. none of these

Answer : 2

Question 11 : The water being used in dairy industry should contain not more than

  1. 5 proteolytic and/or lipolytic organisms per ml
  2. 10 proteolytic and/or lipolytic organisms per ml
  3. 15 proteolytic and/or lipolytic organisms per ml
  4. 20 proteolytic and/or lipolytic organisms/ml

Answer : 1

Question 12 : The activated sludge process consists of returning a portion of the clarifier

  1. effluent water entering the reactor
  2. influent water coming out of the reactor
  3. influent water entering the reactor
  4. effluent water coming out of the reactor

Answer : 3

Question 13 : Permanent hardness of water may be removed by the addition of

  1. lime
  2. soda ash
  3. potassium permagnate
  4. sodium bicarbonate

Answer : 2

Question 14 : Both temporary and permanent hardness of water can be removed on boiling water with

  1. calcium hydroxide
  2. sodium carbonate
  3. calcium oxide
  4. calcium carbonate

Answer : 2

Question 15 :  Lagoons may be characterized as

  1. anaerobic
  2. facultative
  3. aerated
  4. all of these

Answer : 4

Question 16 : Temporary hardness of water may be removed by adding

  1. calcium hydroxide
  2. calcium carbonate
  3. calcium chloride
  4. sodium bicarbonate

Answer : 1

Question 17 : The maximum desirable limit (BIS of mercury in the drinking water is

  1. 0.05 mg/l
  2. 0.9 mg/l
  3. 0.1 mg/l
  4. 0.001 mg/l

Answer : 4

Question 18 : Which of the following substances are commonly used in a filter?

  1. Charcoal
  2. Sand
  3. Both (1) and (2)
  4. Aluminum chloride

Answer : 3

Question 19 : Biological oxidation processes usually referred as biological treatment, are the most common form of

  1. primary treatment
  2. secondary treatment
  3. tertiary treatment
  4. all of these

Answer : 2

Question 20 : The maximum permissible limit (BIS) of turbidity in drinking water is

  1. 5 NTU
  2. 10 NTU
  3. 15 NTU
  4. 20 NTU

Answer : 2

Question 21 : Sedimentation is a physical process used in wastewater treatment to

  1. remove particles that are less dense than water
  2. remove particles that are more dense than water
  3. remove the pertinacious material from the water
  4. none of the above

Answer : 2

Question 22 : The ultimate source of water is

  1. rivers and lakes
  2. dew and forest
  3. rain and snow
  4. underground and surface

Answer : 3

Question 23 : Which of the following physical method is used as germicidal in modern time for the treatment of drinking water?

  1. Chlorination
  2. Treating with potassium permagnate
  3. UV radiation
  4. Treating with bleaching powder

Answer : 3

Question 24 : Sanitizer used specifically for vitreous enamel are

  1. strong alkalis
  2. strong acids
  3. weak alkali with sodium silicate
  4. none of these

Answer : 3

Question 25 : The common methods used for disinfection in waste water treatment plants are

  1. chlorination
  2. UV light
  3. both (a) and (b)
  4. Phenolic solvent

Answer : 3

Question 26 : Inhibitors are used along with sanitizer to

  1. improve their action
  2. to prevent corrosion
  3. both (a) and (b)
  4. none of these

Answer : 2

Question 27 : Sanitizers used for rubber made equipments are

  1. strong acids
  2. strong alkalis
  3. combination of both
  4. none of these

Answer : 2

Question 28 : Application of quaternary ammonium compounds as sanitizing agents tends to

  1. favor gram positive bacteria
  2. decrease gram positive bacteria
  3. increase the percentage of gram(-)ve rods on utensils
  4. none of the above

Answer : 3

Question 29 : Permanent hardness of water is caused by the presence of

  1. bicarbonates of calcium and magnesium
  2. carbonates of sodium and potassium
  3. chlorides and sulfates of calcium and magnesium
  4. phosphates of sodium and potassium

Answer : 3

Question 30 : According to BIS the maximum permissible limit of dissolved solids in drinking water is

  1. 1000 mg/l
  2. 500 mg/l
  3. 2000 mg/l
  4. 2000 mg/l

Answer : 3

Question 31 : Acid used mostly for removal of milk stone is

  1. phosphoric acid
  2. nitric acid
  3. gluconic acid
  4. tartaric acid

Answer : 2

Question 32 : Which of the following chemical is sometime added in the process of coagulation and flocculation?

  1. Aluminum sulphate
  2. Aluminum oxide’
  3. Calcium chloride
  4. None of these

Answer : 1

Question 33 : Hardness of water does not

  1. have any bad effect in boiler
  2. make cooking of foods difficult
  3. make it unfit for drinking
  4. cause difficulty in the washing of clothes with soaps

Answer : 3

Question 34 : Permanent hard water may be softened by passing it through

  1. sodium silicate
  2. sodium bicarbonate
  3. sodium hexametaphosphate
  4. sodium phosphate

Answer : 3

Question 35 : 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

  1. 10% calcium chloride solution
  2. 10% magnesium sulfate solution
  3. 10% magnesium chloride solution
  4. 10% sodium chloride solution

Answer : 4

Question 36 : Temporary hardness of water is caused by the presence of

  1. chlorides of calcium and magnesium
  2. sulfates of calcium and magnesium
  3. bicarbonates of calcium and magnesium
  4. carbonates of sodium and potassium

Answer : 3

Question 37 : Secondary treatment uses __________ to consume wastes

  1. micro-organisms
  2. chemicals
  3. filtration
  4. none of these

Answer : 1

Question 38 : The maximum desirable limit Bureau of Indian Standards (BIS) of lead in the drinking water is

  1. 0.05 mg/l
  2. 0.09 mg/l
  3. 0.1 mg/l
  4. 1.0 mg/l

Answer : 1

Question 39 : Zeolite softening process removes

  1. only temporary hardness of water
  2. only permanent hardness of water
  3. both temporary and permanent hardness of water’
  4. the dissolved gases in permanent hard water

Answer : 3

Question 40 : Conventional tertiary treatment is

  1. chemical coagulation and flocculation
  2. filtration
  3. sedimentation
  4. none of these

Answer : 1

Question 41 : The maximum desirable limit (BIS) of total hardness (as CaCo3) in drinking water is

  1. 600 ppm
  2. 300 ppm
  3. 500 ppm
  4. 1000 ppm

Answer : 2

Question 42 : The chemical oxygen demand (COD)measures the

  1. amount of oxygen required for growth of microorganisms in water
  2. amount of oxygen that would be removed from the water in order to oxidize pollution
  3. amount of oxygen required to oxidize the calcium present in waste water
  4. none of the above

Answer : 2