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WorksheetsWastewater treatment and residual chlorine
Total questions: 18
Worksheet time: 10mins
Why is chlorine added in water?
To remove metal ions
To remove organic compounds
To destroy pathogenic micro-organisms
To increase the salt content of water
What is residual chlorine?
Chlorine added for disinfection
Chlorine remaining after disinfection process is complete
Chlorine actually used for disinfection
What is break point chlorination?
The chlorine added to form chloramines and chloro-organic compounds
Adding chlorine to destroy chloramines
The point at which the chlorine added exceeds oxidant demand
The point at which chlorine breaks down in to chloride ions
Which of the following is termed as free available chlorine?
Hypochlorous acid
Hypochlorite ions
Molecular chlorine
All of the above
At what pH does chlorine exists as molecular chlorine?
3
5
<5
<10
When the pH is between 5 and 10, the chlorine in the water is in the form of ________
Hypochlorous acid
Hypochlorite ions
Molecular chlorine
Hypochlorous acid hypochlorite ions
At what pH, chlorine in water acts as only hypochlorite ions?
<5
>5
<10
>10
Chlorine which gets consumed in the oxidation of impurities before disinfection is ______________
Free chlorine
Residual chlorine
Chlorine demand
Residual demand
The chlorine remaining at the end of water treatment that serves as a disinfectant is ___________
Free chlorine
Free Residual chlorine
Chlorine demand
Residual demand
The permissible limit of free residual chlorine is ___________ppm
0.2
0.6
1
10
Hypochlorous acid is ______ times effective as hypochlorite ions for disinfection.
50
10
80
5
A small city gets its drinking water from the river running through its center. This river is fed by rivers that flow down the mountains nearby.How would excessive rainfall in the mountains most likely affect the turbidity of this local water source?
A. Heavy rainfall would decrease the turbidity of the river downstream.
B. Heavy rainfall would increase the turbidity of the river downstream.
C. Heavy rainfall would increase the turbidity of only rivers upstream.
D. Heavy rainfall would decrease the turbidity of only rivers upstream.
The Environmental Protection Agency was assigned with which task?
setting standards and governing the cleanliness of water used by Americans
setting standards and governing the highways and interstates in the United States
setting standards and governing the use of national parks and monuments in the United States
setting standards and governing the civil and commercial air transportation in the United States.
Which steps in the water-treatment process use positively charged chemicals to balance negatively charged sediment, leading to the formation of larger particles when these oppositely charged particles combine?
sedimentation and coagulation
disinfection and sedimentation
coagulation and flocculation
disinfection and flocculation
What does a pH of 7 most likely indicate about the water quality?
The water is a strong base
The water is highly acidic
The water is toxic to drink
The water is safe to drink
The formula for hypochlorous acid is
(a)
Which curve shows that there were more nitrogen-containing compounds in the sample than the other?
the blue curve
the red curve
they have the same amount of nitrogen compounds
you cannot tell from these graphs
Treatment of sewage can be done by ___________, ___________, and _____________ types of processes.
Physical
Chemical
Biological
Mechanical
