List Of 100 Environmental Engineering Objective Questions
1.The type of valve, which is provided on the suction pipe in a tube-well, is
air relief valve
reflux valve
pressure relief valve
sluice valve
ANSWER : : reflux valve
2.Which of the following values of pH represents a stronger acid?
2
5
7
10
ANSWER : : 2
3.The population of a town in three consecutive years are 5000, 7000 and 8400 respectively. The population of the town in the fourth consecutive year according to geometrical increase method is
9500
9800
10100
10920
ANSWER : : 10920
4.Standard EDTA (ethylene diamine tetra acetic acid) solution is used to determine the
hardness in water
turbidity in water
dissolved oxygen in water
residual chlorine in water
ANSWER : : hardness in water
5.The distribution mains are designed for
maximum daily demand
maximum hourly demand
average daily demand
maximum hourly demand on maximum day
ANSWER : : maximum hourly demand on maximum day
6.The maximum discharge of a tube-well is about
5 litres/sec
50 litres/sec
500 litres/sec
1000 litres/see
ANSWER : : 50 litres/sec
7.The maximum permissible limit for flouride in drinking water is
0.1 mg/litre
1.5 mg/litre
5 mg/litre
10 mg/litre
ANSWER : : 1.5 mg/litre
8.The polluted water is one which
contains pathogenic bacteria
consists of undesirable substances rendering it unfit for drinking and domestic use
is safe and suitable for drinking and domestic use
is contaminated
ANSWER : : consists of undesirable substances rendering it unfit for drinking and domestic use
9., The depression of water table in a well due to pumping will be maximum
at a distance R from the well
close to the well
at a distance R/2 from the well
none of the above
ANSWER : re R is the radius of influence
10.The suitable method of forecasting population for a young and rapidly increasing city is
arithmetical increase method
geometrical increase method
incremental increase method
graphical method
ANSWER : : geometrical increase method
11.If the coliform bacteria is present in a sample of water, then the coliform test to be conducted is i) presumptive coliform test ii) confirmed coliform test iii) completed coliform test The correct answer is
only (i)
both (i) and (ii)
both (i) and (iii)
all (i), (ii) and (iii)
ANSWER : : all (i), (ii) and (iii)
12.The hourly variation factor is usually taken as
1.5
1.8
2.0
2.7
ANSWER : : 1.5
13.Alkalinity in water is expressed as milli-grams per litre in terms of equivalent
calcium carbonate
magnesium carbonate
sodium carbonate
calcium hydroxide
ANSWER : : calcium carbonate
14.The most common cause of acidity in water is
carbon dioxide
oxygen
hydrogen
nitrogen
ANSWER : : carbon dioxide
15.Ground water is usually free from
suspended impurities
dissolved impurities
both suspended and dissolved impuri�ties
none of the above
ANSWER : : suspended impurities
16.The per capita consumption of a locality is affected by i) climatic conditions ii) quality of water iii) distribution pressure The correct answer is
only (i)
both (i) and (ii)
both (i) and (iii)
all (i), (ii) and (iii)
ANSWER : : all (i), (ii) and (iii)
17.The phenolic compounds in public water supply should not be more than
0.1 ppm
0.01 ppm
0.001 ppm
0.0001 ppm
ANSWER : : 0.001 ppm
18.If the average daily consumption of a city is 100,000 m3, the maximum daily con�sumption on peak hourly demand will be
100000m3
150000m3
180000m3
270000 m3
ANSWER : : 270000 m3
19.As compared to shallow-wells, deep wells have
more depth
less depth
more discharge
less discharge
ANSWER : : more discharge
20.As compared to geometrical increase method of forecasting population, arithmetical increase method gives
lesser value
higher value
same value
accurate value
ANSWER : : lesser value
21.Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)
N = y + R
y = N + R
R = N + y
R > (N + y)
ANSWER : : N = y + R
22.Which of the following causes a decrease in per capita consumption ?
use of metering system
good quality of water
better standard of living of the people
hotter climate
ANSWER : : use of metering system
23.The devices which are installed for drawing water from the sources are called
aquifers
aquiclude
filters
intakes
ANSWER : : intakes
24.Which of the following is not a water borne disease ?
dysentery
cholera
typhoid
maleria
ANSWER : : maleria
25.Alum as a coagulant is found to be most effective when pH range of water is
2 to 4
4 to 6
6 to 8
8 to 10
ANSWER : s:c
26.The detention period in coagulation tanks is usually kept as
1 to 2 minutes
30 to 45 minutes
2 to 6 hours
2 to 6 days
ANSWER : : 2 to 6 hours
27.Air binding phenomena in rapid sand filters occur due to
excessive negative head
mud ball formation
higher turbidity in the effluent
low temperature
ANSWER : : excessive negative head
28.The chemical most commonly used to increase speed of sedimentation of sewage is
sulphuric acid
copper sulphate
lime
sodium permanganate
ANSWER : : lime
29.The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally
less and more
less and less
more and less
more and more
ANSWER : : more and less
30.The alum, when added as a coagulant in water
does not require alkalinity in water for flocculation
does not affect pH value of water
increases pH value of water
decreases pH value of water
ANSWER : : decreases pH value of water
31.If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to
total alkalinity
total hardness
total hardness – total alkalinity
non carbonate hardness
ANSWER : : total alkalinity
32.The effective size of sand particles used in slow sand filters is
0.25 to 0.35 mm
0.35 to 0.60 mm
0.60 to 1.00 mm
1.00 to 1.80 mm
ANSWER : : 0.25 to 0.35 mm
33.The amount of coagulant needed for coagulation of water increases with i) increase in turbidity of water ii) decrease in turbidity of water iii) increase in temperature of water iv) decrease in temperature of water The correct answer is
(i) and (ii)
(i)and(iv)
(ii) and (iii)
(ii) and (iv)
ANSWER : : (i)and(iv)
34.In water treatment, rapid gravity filters are adopted to remove
dissolved organic substances
dissolved solids and dissolved gases
floating solids and dissolved inorganic solids
bacteria and colloidal solids
ANSWER : : bacteria and colloidal solids
35.The settling velocity of a particle in a sedimentation tank increases if
particle size is decreased
the surface area of tank is increased
the depth of tank is decreased
none of the above
ANSWER : : none of the above
36.Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about
10 to 25
50
75
100
ANSWER : : 75
37.The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of
1 mg/litre
10 mg/litre
100 mg/litre
1000 mg/litre
ANSWER : : 10 mg/litre
38.For a given discharge, the efficiency of sedimentation tank can be increased by
increasing the depth of tank
decreasing the depth of tank
increasing the surface area of tank
decreasing the surface area of tank
ANSWER : : increasing the surface area of tank
39.As compared to rapid sand filters, slow sand filters give i) slower filtration rate ii) higher filtration rate iii) lesser efficiency in removal of bacteria iv) higher efficiency in removal of bacteria The correct answer is
(i) and (ii)
(ii) and (iii)
(i) and (iv)
(ii) and (iv)
ANSWER : : (i) and (iv)
40.Residual chlorine in water is determined by
starch iodide method
orthotolidine method
both (a) and (b)
none of the above
ANSWER : : both (a) and (b)
41.The settling velocity of a particle in a sedimentation tank depends on
depth of tank
surface area of tank
both depth and surface area of tank
none of the above
ANSWER : : surface area of tank
42.Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below:
Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true but R is false.
A is false but R is true.
ANSWER : : Both A and R are true and R is the correct explanation of A.
43.The length of rectangular sedimentation tank should not be more than
B
2B
4B
8B
ANSWER : re B is the width of the tank
44.The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about
0.01 to 0.05 ppm
0.05 to 0.5 ppm
0.5 to 1.0 ppm
1.0 to 5.0 ppm
ANSWER : : 0.05 to 0.5 ppm
45.The rate of filtration in slow sand filters in million litres per day per hectare is about
50 to 60
100 to 150
500 to 600
1400 to 1500
ANSWER : : 50 to 60
46.The overflow rate for plain sedimentation tanks is about
500 to 750 litres/hour/ m2
1000 to 1250 litres/hour/ m2
1250 to 1500 litres/hour/m2
1500 to 2000 litres/hour/m2
ANSWER : : 500 to 750 litres/hour/ m2
47.Orthotolidine test is used for determination of
dissolved oxygen
residual chlorine
biochemical oxygen demand
dose of coagulant
ANSWER : : residual chlorine
48.The velocity of flow of water in a sedimentation tank is about
5 to 10 cm/sec.
15 to 30 cm/sec.
15 to 30 cm/minute
15 to 30 cm/hour
ANSWER : : 15 to 30 cm/minute
49.On standard silica scale, the turbidity in drinking water should be limited to
10 ppm
20 ppm
30 ppm
50 ppm
ANSWER : : 10 ppm
50.The major disadvantage of lime soda process of water softening is that
it is unsuitable for turbid and acidic water
huge amount of precipitate is formed which creates a disposal problem
the effluent cannot be reduced to zero hardness
it is unsuitable for softening the water of excessive hardness
ANSWER : : huge amount of precipitate is formed which creates a disposal problem
51.In chlorination, with the rise in temperature of water, death rate of bacteria
increases
decreases
remains unaffected
none of the above
ANSWER : : increases
52.The process in which the chlorination is done beyond the break point is known as
prechlorination
post chlorination
super chlorination
break point chlorination
ANSWER : : super chlorination
53.Disinfection of water results in
removal of turbidity
removal of hardness
killing of disease bacteria
complete sterilisation
ANSWER : : killing of disease bacteria
54.Chlorine demand of water is equal to
applied chlorine
residual chlorine
sum of applied and residual chlorine
difference of applied and residual chlorine
ANSWER : : difference of applied and residual chlorine
55.Which of the following chemical compounds can be used for dechlorination of water ?
carbon dioxide
bleaching powder
sulphur dioxide
chloramines
ANSWER : : sulphur dioxide
56.The treatment of water with bleaching powder is known as
prechlorination
super chlorination
dechlorination
hypochlorination
ANSWER : : hypochlorination
57.The suitable layout of a distribution system for irregularly growing town is
dead end system
grid iron system
radial system
ring system
ANSWER : : dead end system
58.The suitable method for disinfection of swimming pool water is
ultra violet rays treatment
lime treatment
by using potassium permanganate
chlorination
ANSWER : : ultra violet rays treatment
59.The percentage of chlorine in fresh bleaching powder is about
10 to 15
20 to 25
30 to 35
40 to 50
ANSWER : : 30 to 35
60.As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is
smaller
larger
same
none of the above
ANSWER : : smaller
61.The rate of Alteration of pressure filters is
less than that of slow sand filters
in between the filtration rate of slow sand filters and rapid sand filters
greater than that of rapid sand filters
equal to that of slow sand filters
ANSWER : : greater than that of rapid sand filters
62.As compared to cast iron pipes, steel pipes are
heavier
stronger
costlier
less susceptible to corrosion
ANSWER : : stronger
63.Period of cleaning of slow sand filters is about
24 – 48 hours
10-12 days
2-3 months
1-2 year
ANSWER : : 2-3 months
64.Cleaning is done by i) scraping and removal in filters slow sand ii) back washing in slow sand filters iii) scraping and removal in filters rapid sand iv) back washing in rapid sand filters The correct answer is
(i) and (ii)
(ii) and (iii)
(i) and (iv)
(ii) and (iv)
ANSWER : : (i) and (iv)
65.Disinfection efficiency is
reduced at higher pH value of water
unaffected by pH value of water
increased at higher pH value of water
highest at pH value equal to 7
ANSWER : : reduced at higher pH value of water
66.Activated carbon is used for
disinfection
removing hardness
removing odours
removing corrosiveness
ANSWER : : removing odours
67.The layout of distribution system in which water flows towards the outer periphery is
ring system
dead end system
radial system
grid iron system
ANSWER : : radial system
68.The disinfection efficiency of chlorine increases by i) decreasing the time of contact ii) decreasing the temperature of water iii) increasing the temperature of water The correct answer is
only (i)
both (i) and (ii)
both (i) and (iii)
only (iii)
ANSWER : : only (iii)
69.The suitable layout of distribution system for a city with roads of rectangular pattern is
grid iron system
dead end system
ring system
radial system
ANSWER : : grid iron system
70.Which of the following compounds is widely used for algae control ?
sodium sulphate
copper sulphate
sodium chloride
calcium chloride
ANSWER : : copper sulphate
71.The commonly used material for water supply pipes, which has the properties of being strong, not easily corroded and long life but is heavy and brittle is
steel
cast iron
copper
reinforced cement concrete
ANSWER : : cast iron
72.Double filtration is used
to increase the filtration slow sand filters capacity of
to increase the filtration rapid sand filters capacity of
for isolated buildings like pools, hotels etc swimming
all of the above
ANSWER : : to increase the filtration slow sand filters capacity of
73.In lime-soda process
only carbonate hardness is removed
only non-carbonate hardness is re-moved
lime reduces the carbonate hardness and soda-ash removes the non-carbo�nate hardness
lime reduces the non-carbonate hard-ness and soda-ash removes the carbo�nate hardness
ANSWER : : lime reduces the carbonate hardness and soda-ash removes the non-carbo�nate hardness