WorksheetsEnvironmental Engineering (Set-7)
Total questions: 25
Worksheet time: 13mins
Select the secondary air pollutants among the following :
a) ozone and carbon monoxide
b) peroxy-acyl-nitrate(PAN) and ozone
c) peroxy-acyl-nitrate(PAN) and carbon monoxide
d) carbon monoxide and sulphur dioxide
The primary pollutant caused by incomplete combustion of organic matter is
a) ozone
b) carbon monoxide
c) sulphur dioxide
d) none of the above
Select the primary air pollutant among the following :
a) sulphur dioxide and nitrogen oxides
b) ozone and carbon monoxide
c) sulphur dioxide and ozone
d) nitrogen oxide and ozone
The spray tower can be used to control
a) gaseous pollutants only
b) particulate pollutants only
c) both (a) and (b)
d) none of the above
The specific standard for SO2 under US Ambient Air Quality standards is 80 µg/m3 . This is approximately equivalent to
a) 0.03 ppm
b) 0.05 ppm
c) 0.08 ppm
d) 8 ppm
The depletion of ozone in the outer atmosphere may results in increased
a) heart attack cases
b) skin cancer cases
c) asthma cases
d) none of above
The rain is generally termed as acidic, if ph value of rain water falls below
a) 3
b) 5
c) 7
d) 8
The acid rains are caused by the following pollutants
a) SO2 and O3
b) SO2 and NOx
c) NOx and O3
d) CO and So2
To express sound levels in decibles, sound pressure levels are usually adopted on a reference scale of
a) 10 µPa
b) 20 µPa
c) 50 µPa
d) 100 µPa
The height of chimney required for effective disposal of 27 kg/hr of SO2 emission is
a) 42 m
b) 30 m
c) 222 m
d) 81 m
If the actual height of a stack is 750 m and plume height is 8m, then the effective height of the stack is
a) 150 m
b) 142 m
c) 158 m
d) 166 m
When the Adiabatic Lapse Rate (ALR) is more than Environmental Lapse Rate (ELR), then the ELR can be called as
a) super adiabatic lapse rate
b) sub adiabatic lapse rate
c) dry adiabatic lapse rate
d) wet adiabatic lapse rate
When Environmental Lapse Rate(ELR) is more than Adiabatic Lapse Rate (ALR), then the environment is said to be
a) stable
b) unstable
c) neutral
d) none of above
Temporary hardness in water is caused by the presence of
a) bicarbonate of Ca and Mg
b) sulphates of Ca and Mg
c) chloride of Ca and Mg
d) nitrates of Ca and Mg
Blue baby disease ( methemoglobinemia ) in children is caused by the presence of excess
a) chlorides
b) nitrates
c) fluorides
d) lead
Two sample of water A and B have pH values of 4.4 and 6.4 respectively. How many times acidic sample A is than sample B ?
a) 0
b) 50
c) 100
d) 200
If presents in water, chlorination of water does not reduced the
a) ammonia content
b) organic matter content
c) B.O.D
d) dissolved oxygen content
Dechlorination of water is achieved by adding
a) sodium thiosulphate
b) sodium sulphate
c) sodium hexametaphosphate
d) sodium bisulphate
the efficiency of a sedimentation tank does not depend upon
a) detention time
b) depth of the tank
c) length of the tank
d) horizontal velocity of water
A city supply of 15000 cubic metres of water per day is treated with a chlorine dosage of 0.5 ppm. For this purpose, the requirement of 25% bleaching powder per day would be
a) 300 kg
b) 75 kg
c) 30 kg
d) 7.5 kg
When the coefficient of rugosity is increased from 0.01 to 0.02, the gradient of a pipe of a given diameter to carry the same velocity will be
a) increased by 4 times
b) increased by 2 times
c) decreased by √2 times
d) decreased by 4 times
Which one of the following statements is true of trickling filter sludge ?
a) It has a comparatively low sludge volume index
b) It is more difficult to dewater than activated sludge
c) It has a comparatively low concentration of sludge solids
d) It is bulky
BOD is preferred to COD as an index of sewage concentration because
BOD represents both carbonaceous and nitrogenous organic matter while COD may indicate carbonaceous
BOD test is easier to perform and gives more reliable results
BOD relates specifically to putrescible organic matter which is the most objectionable sewage constituent
COD relates to the impurities which can only be removed by chemical treatment which is expensive
Under Indian conditions, the average per capita contribution of BOD is
a) 10 to 20 gm/d
b) 25 to 35 gm/d
c) 35 to 50 gm/d
d) 50 to 70 gm/d
Sewage sickness relates to
a) toxicity of sewage interfering with response to treatment
b) destruction of aquatic flora and fauna due to gross pollution of receiving bodies of water by sewage
c) reduction in the waste purifying capacity of the soil
d) clogging of pores in soil due to excessive application of sewage to land, obstructing aeration and landing to septic conditions
