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Worksheets22/01/26-Civilwar-Overseer grade 1-coagulation & filtration
Total questions: 10
Worksheet time: 10mins
Name
Class
Date
1.
The basic principle of coagulation is based on
a)
Oxidation of impurities
b)
Neutralization of negative charges on colloidal particles
c)
Increase in water temperature
d)
Biological decomposition
2.
Flocs formed during coagulation are best described as
a)
Gelatinous and sticky precipitates
b)
Crystalline deposits
c)
Gaseous bubbles
d)
Hardened mineral particles
3.
In the Double Layer Theory the Stern layer is
a)
A wide layer of same charge
b)
A thin rigid layer of opposite charge
c)
A neutral boundary zone
d)
The outermost diffused layer
4.
The most commonly used coagulant in water treatment plants is
a)
Sodium aluminate
b)
Copperas
c)
Alum
d)
Ferric chloride
5.
The parameter used to determine the optimum dose of a coagulant is
a)
Turbidity test
b)
pH test
c)
Jar test
d)
Hardness test
6.
Typical detention time for sedimentation after coagulation is
a)
30–60 minutes
b)
1–2 hours
c)
2–4 hours
d)
6–8 hours
7.
The biological layer formed on slow sand filter media is known as
a)
Floc blanket
b)
Biofilm
c)
Slime mat
d)
Schmutzdecke
8.
The rate of filtration for a slow sand filter generally lies in the range of
a)
3000–6000 L/hr/m²
b)
6000–15000 L/hr/m²
c)
100–200 L/hr/m²
d)
500–1000 L/hr/m²
9.
Backwashing is the method of cleaning used in
a)
Slow sand filters
b)
Roughening filters
c)
Rapid sand filters
d)
Plain sedimentation tanks
10.
Pressure filters are most commonly used for water supply in
a)
Rural villages
b)
Large irrigation projects
c)
Swimming pools and hospitals
d)
River treatment plants
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