Environmental Engineering Multiple Choice Questions on “Dry Weather Flow”.
1. _________ is the flow through sewers available during non-rainfall period.
a) Gradually varied flow
b) Rapidly varied flow
c) Dry weather flow
d) Storm water flow
Answer: c
Clarification: Dry weather flow is the flow through sewers available during non-rainfall period. It consists of domestic sewage and waste water sewage.
2. _______ is the additional flow occurring during rainy season.
a) Gradually varied flow
b) Rapidly varied flow
c) Dry weather flow
d) Storm water flow
Answer: d
Clarification: The storm water flow is the additional flow occurring during the rainy season. It consists of runoff from roofs, streets or open spaces during rainfall.
3. Which flow is also called as sanitary sewage?
a) Dry weather flow
b) Storm weather flow
c) Uniform flow
d) Non uniform flow
Answer: a
Clarification: Dry weather flow is the quantity of wastewater that flows through a sewer in dry weather when no storm water is present in the sewer.
4. Which of the following factor does not effect the dry weather flow?
a) Rate of water supply
b) Temperature conditions
c) Population growth
d) Infiltration of ground water
Answer: b
Clarification: There are four factors that affect the dry weather flow, namely the rate of water supply, population growth, type of area served and infiltration of ground water.
5. The quantity of waste water is assumed to be ___________ % of the quantity of water supply.
a) 40
b) 50
c) 60
d) 80
Answer: d
Clarification: The quantity of waste water is assumed to be 80 % of the quantity of water supply when no extra water enters the sewer.
6. The sewer should be designed for a minimum of ______ litres of waste water per capita per day.
a) 50
b) 100
c) 150
d) 1000
Answer: c
Clarification: Sewer is an underground carriage system that takes impure water from houses and commercial buildings through pipes to treatment units and they should be designed for a minimum of 150 litres of waste water per capita per day.
7. The size of the town is 15,000. What is the density of population per hectare?
a) 50
b) 75
c) 100
d) 200
Answer: d
Clarification: When the size of the town is between 5000 and 20,000, the density of population per hectare is between 150 and 200.
8. The design period of main and branch sewer is ___________
a) 5years
b) 10years
c) 30years
d) 40years
Answer: c
Clarification: The main and branch sewer is designed for the population that may occur at the end of one generation of 30 years.This period of 30 years is called a design period.
9. ___________ is the process in which ground water unfiltrate into the sewers.
a) Exfiltration
b) Infiltration
c) Filtration
d) Osmosis
Answer: b
Clarification: Infiltration is the process in which ground water unfiltrate into the sewers. It increases the load on the treatment work.
10. ________ is the process which indicates the flow of waste water from the sewer into the ground.
a) Exfiltration
b) Infiltration
c) Filtration
d) Osmosis