Q.1) The suitable method of forecasting population for a young and rapidly increasing city is :
A) Arithmetical increase method
B) Geometrical increase method
C) Incremental increase method
D) Graphical method
Option (B)
Explanation :
Arithmetical Increase Method : This method gives lowest forecasting value and assumes the growth of population at constant rate. It is suitable for large and old city.
Geometric Increase Method : This method gives higher values and assumes the growth of population to be constant from decade to decade. Ii is suitable for new and rapidly growing city.
Incremental Increase Method : This method is an improvement of Arithmetic Increase Method and assumes the growth of population in increasing order. It is suitable for average size town.
Graphical Method : This method involves accurately plotting the population of the past few decades on a graph using a proper scale, and then extrapolating the population curve to predict future population trends.
Q.2) The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about :
A) 0.01 – 0.05 ppm
B) 0.05 – 0.5 ppm
C) 0.5 – 1.0 ppm
D) 1.0 – 5.0 ppm
Option (B)
Q.3) The velocity of flow of water in a sedimentation tank is about :
A) 5 – 10 cm/s
B) 15 – 30 cm/s
C) 15 – 30 cm/min
D) 15 – 30 cm/hr
Option (C)
Q.4) Alum as a coagulant is found to be most effective when the pH range of water is :
A) 2 – 4
B) 4 – 6
C) 6 – 8
D) 8 – 10
Q.5) The effective size of sand particles used in slow sand filters is :
A) 0.25 – 0.35 mm
B) 0.35 – 0.60 mm
C) 0.60 – 1.00 mm
D) 1.00 – 1.80 mm
Option (A)
Q.6) Disinfection of water results in :
A) Removal of turbidity
B) Removal of hardness
C) Killing of disease bacteria
D) Complete sterilisation
Option (C)
Explanation :
Disinfection is a proceess of adding chemical to water such as chlorine, to kill or eradicate bacterias present in water after filtration.
Q.7) The treatment of water with bleaching powder is known as :
A) Prechlorination
B) Superchlorination
C) Dechlorination
D) Hypochlorination
Option (D)
Explanation :
Prechlorination : It is a process of adding chlorine in water before under going to treatment process.
Superchlorination : It is a process of adding large amount of chlorine to water to increase the chlorine concentration rapidly.
Dechlorination : It is a process of removing excess amount of chlorine from water.
Hyperchlorination : It is the process of adding a controlled amount of chlorine to water to achieve a residual concentration of free chlorine.
Q.8) The major disadvantage of lime soda process of water softening is that :
A) It is unsuitable for turbid and acidic water
B) Huge amount of precipitate is formed which creates a disposal problem
C) The effluent cannot be reduced to zero hardness
D) It is unsuitable for softening the water of excessive hardness
Option (B)
Q.9) Which of the following compound is widely used for algae control?
A) Sodium sulphate
B) Copper sulphate
C) Sodium chloride
D) Calcium chloride
Option (B)
Q.10) The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipelines intersect is :
A) Check valve
B) Sluice valve
C) Safety valve
D) Scour valve
Option (B)
Q.11) Sewerage system is usually designed for :
A) 10 years
B) 25 years
C) 50 years
D) 75 years
Option (B)
Q.12) Most suitable section of sewer in separate sewage system is :
A) Rectangular section
B) Circular section
C) Standard form of egg-shaped sewer
D) Modified egg-shaped section
Option (B)
Q.13) Dissolved oxygen in streams is :
A) Maximum at noon
B) Minimum at noon
C) Maximum at midnight
D) Same throughout the day
Option (A)
Explanation :
Dissolved Oxygen is the amount of oxygen available in water to aquatic organisms.
Q.14) Which of the following unit works in anaerobic conditions?
A) Sludge digestion tank
B) Sedimentation tank
C) Activated sludge treatment
D) Trickling filters
Option (A)
Q.15) The maximum efficiency of BOD removal is achieved in :
A) Oxidation pond
B) Oxidation ditch
C) Aerated lagoons
D) Trickling filters
Option (B)
Q.16) The gas from the sludge digestion tank is mainly composed of :
A) Nitrogen
B) Carbon dioxide
C) Hydrogen sulphide
D) Methane
Option (D)
Q.17) The biochemical treatment of sewage effluents is essentially a process of :
A) Oxidation
B) Dehydration
C) Reduction
D) Alkalinization
Option (A)
Q.18) Incrustation of the tubewell pipes may result in :
A) Discharge of highly corrosive acidic water
B) Discharge of highly alkaline water
C) Reduced discharge from tube well
D) Excessive discharge of sand with water
Option (C)
Q.19) The primary pollutant caused by incomplete combustion of organic matter is :
A) Ozone
B) Carbon monoxide
C) Sulphur dioxide
D) None of the above
Option (B)
Q.20) Blue baby disease (methemoglobinemia) in children is caused by the presence of excess :
A) Chlorides
B) Nitrates
C) Fluorides
D) Lead
Option (B)
Explanation :
Blue Baby disease also known as Infant methemoglobinemia is a condition where baby’s skin turns blue. Methemoglobinemia, a condition where the blood is unable to carry oxygen effectively, is more likely to occur in infants under 12 months of age who consume foods or water containing high levels of nitrate.
In addition to nitrate exposure, certain medications such as benzocaine and dapsone, as well as chemicals like aniline and naphthalene, can also cause methemoglobinemia. Furthermore, several health conditions including anemia, milk protein intolerance, severe metabolic acidosis, and urinary tract infections, can increase the risk of methemoglobinemia in infants.
