Environmental Engineering 15

Objective Questions and Answers of Civil Engineering: Environmental Engineering 15

Subject: Environmental Engineering 15

Part 15: Objective questions and answers of Environmental Engineering


Q1. The amount of coagulant needed for coagulation of water increases with

I) increase in turbidity of water

Ii) decrease in turbidity of water

Iii) increase in temperature of water

Iv) decrease in temperature of water

The correct answer is

a) (i) and (ii)

b) (i)and(iv)

c) (ii) and (iii)

d) (ii) and (iv)


Q2. Cleaning is done by

I) scraping and removal in filters slow sand

Ii) back washing in slow sand filters

Iii) scraping and removal in filters rapid sand

Iv) back washing in rapid sand filters

The correct answer is

a) (i) and (ii)

b) (ii) and (iii)

c) (i) and (iv)

d) (ii) and (iv)


Q3. As compared to rapid sand filters, slow sand filters give

I) slower filtration rate

Ii) higher filtration rate

Iii) lesser efficiency in removal of bacteria

Iv) higher efficiency in removal of bacteria the correct answer is

a) (i) and (ii)

b) (ii) and (iii)

c) (i) and (iv)

d) (ii) and (iv)


Q4. The percentage of filtered water, which is used for backwashing in rapid sand filters, is about

a) 0.2 to 0.4

b) 0.4 to 1.0

c) 2 to 4

d) 5 to 7


Q5. The detention period in coagulation tanks is usually kept as

a) 1 to 2 minutes

b) 30 to 45 minutes

c) 2 to 6 hours

d) 2 to 6 days


Q6. The chemical most commonly used to increase speed of sedimentation of sewage is

a) Sulphuric acid

b) Copper sulphate

c) Lime

d) Sodium permanganate


Q7. The rate of filtration in slow sand filters in million litres per day per hectare is about

a) 50 to 60

b) 100 to 150

c) 500 to 600

d) 1400 to 1500


Q8. The rate of alteration of pressure filters is

a) Less than that of slow sand filters

b) In between the filtration rate of slow sand filters and rapid sand filters

c) Greater than that of rapid sand filters

d) Equal to that of slow sand filters


Q9. The disinfection efficiency of chlorine increases by

I) decreasing the time of contact

Ii) decreasing the temperature of water

Iii) increasing the temperature of water the correct answer is

a) Only (i)

b) Both (i) and (ii)

c) Both (i) and (iii)

d) Only (iii)


Q10. The process in which the chlorination is done beyond the break point is known as

a) Prechlorination

b) Post chlorination

c) Super chlorination

d) Break point chlorination


Q11. The treatment of water with bleaching powder is known as

a) Prechlorination

b) Super chlorination

c) Dechlorination

d) Hypochlorination


Q12. Which of the following chemical compounds can be used for dechlorination of water?

a) Carbon dioxide

b) Bleaching powder

c) Sulphur dioxide

d) Chloramines


Q13. As compared to higher ph values, the contact period required for efficient chlorination at lower ph values is

a) Smaller

b) Larger

c) Same

d) None of the above


Q14. In lime-soda process

a) Only carbonate hardness is removed

b) Only non-carbonate hardness is re-moved

c) Lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness

d) Lime reduces the non-carbonate hard-ness and soda-ash removes the carbonate hardness


Q15. Which of the following compounds is widely used for algae control?

a) Sodium sulphate

b) Copper sulphate

c) Sodium chloride

d) Calcium chloride


Q16. As compared to cast iron pipes, steel pipes are

a) Heavier

b) Stronger

c) Costlier

d) Less susceptible to corrosion


Q17. The layout of distribution system in which water flows towards the outer periphery is

a) Ring system

b) Dead end system

c) Radial system

d) Grid iron system


Q18. The commonly used material for water supply pipes, which has the properties of being strong, not easily corroded and long life but is heavy and brittle, is

a) Steel

b) Cast iron

c) Copper

d) Reinforced cement concrete


Q19. The method of analysis of distribution system in which the domestic supply is neglected and fire demand is considered is

a) Circle method

b) Equivalent pipe method

c) Electrical analysis method

d) Hardy cross method


Q20. The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is

a) Reflux valve

b) Sluice valve

c) Air relief valve

d) Pressure relief valve


Part 15: Objective questions and answers of Environmental Engineering


Q1. Answer b


Q2. Answer c


Q3. Answer c


Q4. Answer c


Q5. Answer c


Q6. Answer c


Q7. Answer a


Q8. Answer c


Q9. Answer d


Q10. Answer c


Q11. Answer d


Q12. Answer c


Q13. Answer a


Q14. Answer c


Q15. Answer b


Q16. Answer b


Q17. Answer c


Q18. Answer b


Q19. Answer a


Q20. Answer a