This set of Waste Water Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Chlorinators”.
1. Which of the following is not true about gas chlorination systems?
a) Disinfection of swimming pools
b) Improves taste
c) Increases algae
d) Controls slime
View Answer
Explanation: Gas chlorination systems can be used for the disinfection of swimming pools, improving taste, safety and odour of drinking water and for algae and slime control.
2. Which of the following methods are suggested for a water flow of less than 200 Lpm?
a) Hypochlorinators
b) Vacuum chlorinators
c) Direct feed chlorinators
d) Chlorine cylinders
View Answer
Explanation: The simplest method of continuous chlorination of water supply systems for a water flow of less than 200 Lpm is by the use of a hypochlorinator. Hypochlorinators are motor driven pumps which are used to add hypochlorite solutions to water.
3. In hypochlorinators, the hypochlorite solution is fed into the water by means of _________
a) Pumps
b) Injectors
c) Manual methods
d) Tanks
View Answer
Explanation: The pump pulls the hypochlorite solution out of a holding chamber and pumps it into the water to be treated. The venturi effect creates a small vacuum and pulls the chlorine solution into the water.
4. How is the amount of chlorine adjusted in hypochlorinators?
a) Increasing feed water
b) Decreasing chlorine amount
c) Varying stroke length
d) Increasing treatment time
View Answer
Explanation: In hypo chlorinators, the amount of chlorine fed into the water is adjusted either by varying the stroke length or machine speed.
5. _______ used to perform continuous chlorination in smaller systems.
a) Vacuum chlorinators
b) Chlorine cylinders
c) Direct feed chlorinators
d) Hypochlorinators
View Answer
Explanation: The amount of chlorine added can be adjusted by changing the strength of the hypochlorite solution. Hypochlorinators are usually used to perform continuous chlorination in smaller systems.
6. ______ are used when the supply source is greater than 200 Lpm.
a) Chlorinators
b) Vacuum chlorinators
c) Direct feed chlorinators
d) Hypochlorinators
View Answer
Explanation: When the supply source is greater than 200 Lpm, chlorinators are more economical. To introduce chlorine solution to water, devices called chlorinators are used.
7. NaCl is hydrolysed to chlorine and ______
a) Na
b) NaOH
c) NaI
d) NaNO3
View Answer
Explanation: Chlorinators are devices which introduce chlorine solution to water. NaCl is hydrolysed to chlorine (Cl) and NaOH.
8. What is the minimum pressure required to convert chlorine gas to liquid?
a) 3 Ksc
b) 4 Ksc
c) 5 Ksc
d) 6 Ksc
View Answer
Explanation: NaCl is hydrolysed to chlorine (Cl) and NaOH. By pressurizing the Cl gas at 4 to 7 Ksc pressure, Cl gas is converted into liquid and the liquefied chlorine gas is filled and stored in the cylinders of 48.4-kg and 68-kg capacity or in 907-kg (one-ton) container.
9. What is the maximum weight of chlorine cylinders?
a) 807 Kg
b) 907 Kg
c) 957 Kg
d) 997 Kg
View Answer
Explanation: By pressurizing the Cl gas at 4 to 7 Ksc pressure, Cl gas is converted into liquid and the liquefied chlorine gas is filled and stored in the cylinders of 48.4-kg and 68-kg capacity or in 907-kg (one-ton) container.
10. The liquid expands back into a gas as it leaves the cylinder.
a) True
b) False
View Answer
Explanation: The liquid expands back into a gas as it leaves the cylinder. Whenever a substance changes state from a liquid form to a gaseous form, heat is required. The heat which is absorbed by the chlorine as it changes state in the cylinder comes from the surrounding air.
11. If chlorine is drawn off from a cylinder too quickly, the temperature of the air surrounding the tank will increase.
a) True
b) False
View Answer
Explanation: If chlorine is drawn off from a cylinder too quickly, the temperature of the air surrounding the tank will drop and will cause frosting and lower gas flow.
12. What is the maximum draw off rate of chlorine to prevent frosting?
a) 110 Kg
b) 120 Kg
c) 140 Kg
d) 150 Kg
View Answer
Explanation: The draw off rate should be not greater than 150 kg of gas per day from each cylinder to minimize frosting. Cylinders are joined together so that chlorine gas is drawn from several cylinders at a time.
13. What is the instrument used to measure the chlorine feed rate?
a) pH meter
b) Thermometer
c) Rotameter
d) Spectrometer
View Answer
Explanation: Once the gas has entered the chlorinator, the chlorine feed rate is measured using an indicator known as a rotameter.
14. Injector of chlorine feed is also called as _____
a) Rotameter
b) Ejector
c) Feeder
d) Disinfector
View Answer
Explanation: The chlorine gas is pulled into the injector, also known as an ejector. The injector consists of a pipe filled with flowing water.
15. What is the other name for vacuum chlorinators?
a) Disinfector
b) Solution feeder
c) Hypochlorinators
d) Chlorinators
View Answer
Explanation: Vacuum chlorinator is also known as a solution feeder since the chlorine gas is dissolved into a small amount of source water, which is then piped into the main line of water to be chlorinated.
Sanfoundry Global Education & Learning Series – Waste Water Engineering.
To practice all areas of Waste Water Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
- Practice Civil Engineering MCQs
- Check Civil Engineering Books
- Apply for Civil Engineering Internship
- Check Waste Water Engineering Books
