WorksheetsCivil war—Day 19-Oct 15-PWD-Quality of water& treatment of water
Total questions: 10
Worksheet time: 10mins
Name
Class
Date
1.
MPN index is measure of one of the following:
a)
Coliform bacteria
b)
BOD₅
c)
Dissolved oxygen content
d)
Hardness
2.
The following data pertain to a sewage sample: Initial DO = 10 mg/L, Final DO = 2 mg/L, dilution = 1%. The BOD of the given sewage sample is —
a)
8 mg/L
b)
100 mg/L
c)
800 mg/L
d)
10 mg/L
3.
Which one of the following processes of softening water may require recarbonation?
a)
Lime–soda process
b)
Sodium cation exchange process
c)
Demineralization process
d)
Zeolite process
4.
Which of the following tests of water employs Erichrome Black T as an indicator?
a)
Hardness
b)
COD
c)
Residual chlorine
d)
DO
5.
The permissible limit in the absence of an alternate source for hardness of drinking water (in mg/L) as per IS 10500:2012 is —
a)
200
b)
400
c)
300
d)
600
6.
After suspended matter causing colour is removed by centrifugation, the colour obtained is called —
a)
True colour
b)
Apparent colour
c)
Brackish colour
d)
Pure colour
7.
Which one of the following is not a specific criterion for calculating surface overflow rate in sedimentation tank design?
a)
Total quantity of water to be treated
b)
Total surface area available in the tank
c)
Total length of the tank
d)
Total depth of the tank
8.
A water treatment plant has a flow rate of 432 m³/hr. What is the required plan area of a Type-I settling tank to remove 90% of particles with settling velocity 0.12 cm/s?
a)
90 m²
b)
111 m²
c)
120 m²
d)
100 m²
9.
Which one of the following represents the correct sequence of water treatment?
a)
Screening, sedimentation, disinfection, filtration
b)
Screening, filtration, sedimentation, disinfection
c)
Screening, sedimentation, disinfection, aeration
d)
Screening, sedimentation, filtration, disinfection
10.
Chlorine usage in the treatment of 20,000 m³/day is 8 kg/day. The residual after 10 min contact is 0.20 mg/L. The chlorine demand of the water (in mg/L) is —
a)
0
b)
0.2
c)
0.4
d)
0.6
100 %
