Waste Water Engineering Multiple Choice Questions on “Advanced Oxidation Process – Ozonators”.
1. How many oxygen atoms are present in the ozone?
a) 1
b) 2
c) 3
d) 4
Answer: c
Clarification: Ozonation is a chemical water treatment technique based on the infusion of ozone into water. Ozone is a gas composed of three oxygen atoms, which is one of the most powerful oxidants.
2. Ozone is one of the powerful oxidants.
a) True
b) False
Answer: a
Clarification: Ozone is a gas composed of three oxygen atoms, which is one of the most powerful oxidants. Ozonation is a type of advanced oxidation process, involving the production of very reactive oxygen species.
3. _______ is produced by subjecting oxygen to high electric voltage.
a) Carbon-monoxide
b) Carbon-dioxide
c) Pure oxygen
d) Ozone
Answer: d
Clarification: Ozone is produced with the use of energy by subjecting oxygen or high electric voltage or to UV radiation. The required amounts of ozone can be produced at the point of use but the production requires a lot of energy and is therefore costly.
4. Which of the following can be inactivated using ozone?
a) Algae
b) Fungi
c) Protozoa
d) All microbes
Answer: c
Clarification: Ozone is excellent and can even be used to inactivate microorganisms such as protozoa, which are very resistant to conventional disinfectants.
5. Ozone is an unstable gas.
a) True
b) False
Answer: a
Clarification: Ozone is an unstable gas. Under suitable conditions, it splits into O2 and O. Ozonation helps in removing colour, odour and taste of the water.
6. Which of these is not an advantage of Ozonation?
a) Reaction with bacteria
b) Organics degradation
c) Equipment costs
d) Chemicals
Answer: c
Clarification: The advantages of Ozonation is that it rapidly reacts with bacteria, viruses and protozoa over a wide pH range, no chemicals are added to water and also efficient for organics degradation and inorganics removal.
7. Which of the following is not a disadvantage of Ozonation?
a) Chemicals
b) Costs
c) Energy
d) Fire hazard
Answer: a
Clarification: There are various disadvantages of Ozonation such as the equipment costs are really high, requires large amounts of energy, no residual effect, etc.
8. Which of the following is not removed by Ozonation?
a) Iron
b) Manganese
c) Magnesium
d) Bacteria
Answer: c
Clarification: Ozone is a colourless gas that has an odour similar to the smell of the air after a major thunderstorm.
9. What is the maximum time required for ozone degradation?
a) 15 minutes
b) 30 minutes
c) 45 minutes
d) 60 minutes
Answer: b
Clarification: Organic particles and chemicals will be eliminated through either coagulation or chemical oxidation. Ozone is unstable, and it will degrade over a time frame ranging from a few seconds to 30 minutes. The rate of degradation is a function of water chemistry, pH and water temperature.
10. What is the average ozone concentration created during Ozonation?
a) 1000 mg/l
b) 5000 mg/l
c) 10000 mg/l
d) 15000 mg/l
Answer: c
Clarification: In general, an ozonation system includes passing dry, clean air through a high voltage electric discharge, i.e., corona discharge, which creates and ozone concentration of approximately 1% or 10,000 mg/L.
11. Which of the following is not correct regarding Ozonation?
a) Does not requires chemicals
b) Eliminates bad taste
c) Eliminates odour
d) Operational costs are low