Multiple Choice Questions and Answers on Water Treatment
Question 1 : Both temporary and permanent hardness of water can be removed by
- boiling
- distillation
- filtration
- decantation
Answer : 2
Question 2 : Coliform bacteria in water is an indication of the presence of
- radioactive wastes
- excess fertilizer
- decaying animals and plants
- human feces
Answer : 4
Question 3 : The activated sludge process is sometime referred as
- fluid bed biological oxidation system
- fixed bed biological oxidation system
- turning bed biological oxidation system
- none of the above
Answer : 1
Question 4 : BOD stands for
- biochemical oxygen demand
- british oxygen demand
- british oxygen depletion
- biological oxygen depletion
Answer : 1
Question 5 : When temporary hard water is boiled, one of the substances formed is
- calcium bicarbonate
- calcium sulfate
- hydrogen chloride
- 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
- insoluble carbonates
- insoluble zeolites
- insoluble chlorides
- insoluble sulfates
Answer : 2
Question 7 : The methods used for biological treatment are
- lagoon
- activated sludge process
- oxidation ditches
- all of these
Answer : 4
Question 8 : From the following sanitizers which one comes under category of surface active agents?
- Tetra phosphate
- Teepol
- Meta phosphate
- None of these
Answer : 2
Question 9 : The purest form of naturally occurring water is
- rain water
- river water
- pond water
- well water
Answer : 1
Question 10 : Calgon is used for removal of
- sodium carbonate
- permanent hardness of water
- potassium carbonate
- none of these
Answer : 2
Question 11 : The water being used in dairy industry should contain not more than
- 5 proteolytic and/or lipolytic organisms per ml
- 10 proteolytic and/or lipolytic organisms per ml
- 15 proteolytic and/or lipolytic organisms per ml
- 20 proteolytic and/or lipolytic organisms/ml
Answer : 1
Question 12 : The activated sludge process consists of returning a portion of the clarifier
- effluent water entering the reactor
- influent water coming out of the reactor
- influent water entering the reactor
- effluent water coming out of the reactor
Answer : 3
Question 13 : Permanent hardness of water may be removed by the addition of
- lime
- soda ash
- potassium permagnate
- sodium bicarbonate
Answer : 2
Question 14 : Both temporary and permanent hardness of water can be removed on boiling water with
- calcium hydroxide
- sodium carbonate
- calcium oxide
- calcium carbonate
Answer : 2
Question 15 : Lagoons may be characterized as
- anaerobic
- facultative
- aerated
- all of these
Answer : 4
Question 16 : Temporary hardness of water may be removed by adding
- calcium hydroxide
- calcium carbonate
- calcium chloride
- sodium bicarbonate
Answer : 1
Question 17 : The maximum desirable limit (BIS of mercury in the drinking water is
- 0.05 mg/l
- 0.9 mg/l
- 0.1 mg/l
- 0.001 mg/l
Answer : 4
Question 18 : Which of the following substances are commonly used in a filter?
- Charcoal
- Sand
- Both (1) and (2)
- Aluminum chloride
Answer : 3
Question 19 : Biological oxidation processes usually referred as biological treatment, are the most common form of
- primary treatment
- secondary treatment
- tertiary treatment
- all of these
Answer : 2
Question 20 : The maximum permissible limit (BIS) of turbidity in drinking water is
- 5 NTU
- 10 NTU
- 15 NTU
- 20 NTU
Answer : 2
Question 21 : Sedimentation is a physical process used in wastewater treatment to
- remove particles that are less dense than water
- remove particles that are more dense than water
- remove the pertinacious material from the water
- none of the above
Answer : 2
Question 22 : The ultimate source of water is
- rivers and lakes
- dew and forest
- rain and snow
- 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?
- Chlorination
- Treating with potassium permagnate
- UV radiation
- Treating with bleaching powder
Answer : 3
Question 24 : Sanitizer used specifically for vitreous enamel are
- strong alkalis
- strong acids
- weak alkali with sodium silicate
- none of these
Answer : 3
Question 25 : The common methods used for disinfection in waste water treatment plants are
- chlorination
- UV light
- both (a) and (b)
- Phenolic solvent
Answer : 3
Question 26 : Inhibitors are used along with sanitizer to
- improve their action
- to prevent corrosion
- both (a) and (b)
- none of these
Answer : 2
Question 27 : Sanitizers used for rubber made equipments are
- strong acids
- strong alkalis
- combination of both
- none of these
Answer : 2
Question 28 : Application of quaternary ammonium compounds as sanitizing agents tends to
- favor gram positive bacteria
- decrease gram positive bacteria
- increase the percentage of gram(-)ve rods on utensils
- none of the above
Answer : 3
Question 29 : Permanent hardness of water is caused by the presence of
- bicarbonates of calcium and magnesium
- carbonates of sodium and potassium
- chlorides and sulfates of calcium and magnesium
- phosphates of sodium and potassium
Answer : 3
Question 30 : According to BIS the maximum permissible limit of dissolved solids in drinking water is
- 1000 mg/l
- 500 mg/l
- 2000 mg/l
- 2000 mg/l
Answer : 3
Question 31 : Acid used mostly for removal of milk stone is
- phosphoric acid
- nitric acid
- gluconic acid
- tartaric acid
Answer : 2
Question 32 : Which of the following chemical is sometime added in the process of coagulation and flocculation?
- Aluminum sulphate
- Aluminum oxide’
- Calcium chloride
- None of these
Answer : 1
Question 33 : Hardness of water does not
- have any bad effect in boiler
- make cooking of foods difficult
- make it unfit for drinking
- cause difficulty in the washing of clothes with soaps
Answer : 3
Question 34 : Permanent hard water may be softened by passing it through
- sodium silicate
- sodium bicarbonate
- sodium hexametaphosphate
- 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
- 10% calcium chloride solution
- 10% magnesium sulfate solution
- 10% magnesium chloride solution
- 10% sodium chloride solution
Answer : 4
Question 36 : Temporary hardness of water is caused by the presence of
- chlorides of calcium and magnesium
- sulfates of calcium and magnesium
- bicarbonates of calcium and magnesium
- carbonates of sodium and potassium
Answer : 3
Question 37 : Secondary treatment uses __________ to consume wastes
- micro-organisms
- chemicals
- filtration
- none of these
Answer : 1
Question 38 : The maximum desirable limit Bureau of Indian Standards (BIS) of lead in the drinking water is
- 0.05 mg/l
- 0.09 mg/l
- 0.1 mg/l
- 1.0 mg/l
Answer : 1
Question 39 : Zeolite softening process removes
- only temporary hardness of water
- only permanent hardness of water
- both temporary and permanent hardness of water’
- the dissolved gases in permanent hard water
Answer : 3
Question 40 : Conventional tertiary treatment is
- chemical coagulation and flocculation
- filtration
- sedimentation
- none of these
Answer : 1
Question 41 : The maximum desirable limit (BIS) of total hardness (as CaCo3) in drinking water is
- 600 ppm
- 300 ppm
- 500 ppm
- 1000 ppm
Answer : 2
Question 42 : The chemical oxygen demand (COD)measures the
- amount of oxygen required for growth of microorganisms in water
- amount of oxygen that would be removed from the water in order to oxidize pollution
- amount of oxygen required to oxidize the calcium present in waste water
- none of the above
Answer : 2