Environmental Engineering 16

Objective Questions and Answers of Civil Engineering: Environmental Engineering 16

Subject: Environmental Engineering 16

Part 16: Objective questions and answers of Environmental Engineering


Q1. Alum as a coagulant is found to be most effective when ph range of water is

a) 2 to 4

b) 4 to 6

c) 6 to 8

d) 8 to 10


Q2. The alum, when added as a coagulant in water

a) Does not require alkalinity in water for flocculation

b) Does not affect ph value of water

c) Increases ph value of water

d) Decreases ph value of water


Q3. In water treatment, rapid gravity filters are adopted to remove

a) Dissolved organic substances

b) Dissolved solids and dissolved gases

c) Floating solids and dissolved inorganic solids

d) Bacteria and colloidal solids


Q4. The effective size of sand particles used in slow sand filters is

a) 0.25 to 0.35 mm

b) 0.35 to 0.60 mm

c) 0.60 to 1.00 mm

d) 1.00 to 1.80 mm


Q5. Assertion a: slow sand filters are more efficient in removal of bacteria than rapid sand filters.

Reason r : the sand used in slow sand filters is finer than that in rapid sand filters.

Select your answer based on the coding system given below:

a) Both a and r are true and r is the correct explanation of a.

b) Both a and r are true but r is not the correct explanation of a.

c) A is true but r is false.

d) A is false but r is true.


Q6. Air binding phenomena in rapid sand filters occur due to

a) Excessive negative head

b) Mud ball formation

c) Higher turbidity in the effluent

d) Low temperature


Q7. Period of cleaning of slow sand filters is about

a) 24 – 48 hours

b) 10-12 days

c) 2-3 months

d) 1-2 year


Q8. Double filtration is used

a) To increase the filtration slow sand filters capacity of

b) To increase the filtration rapid sand filters capacity of

c) For isolated buildings like pools, hotels etc swimming

d) All of the above


Q9. Disinfection of water results in

a) Removal of turbidity

b) Removal of hardness

c) Killing of disease bacteria

d) Complete sterilisation


Q10. Chlorine demand of water is equal to

a) Applied chlorine

b) Residual chlorine

c) Sum of applied and residual chlorine

d) Difference of applied and residual chlorine


Q11. The percentage of chlorine in fresh bleaching powder is about

a) 10 to 15

b) 20 to 25

c) 30 to 35

d) 40 to 50


Q12. The suitable method for disinfection of swimming pool water is

a) Ultra violet rays treatment

b) Lime treatment

c) By using potassium permanganate

d) Chlorination


Q13. In chlorination, with the rise in temperature of water, death rate of bacteria

a) Increases

b) Decreases

c) Remains unaffected

d) None of the above


Q14. Disinfection efficiency is

a) Reduced at higher ph value of water

b) Unaffected by ph value of water

c) Increased at higher ph value of water

d) Highest at ph value equal to 7


Q15. The major disadvantage of lime soda process of water softening is that

a) It is unsuitable for turbid and acidic water

b) Huge amount of precipitate is formed which creates a disposal problem

c) The effluent cannot be reduced to zero hardness

d) It is unsuitable for softening the water of excessive hardness


Q16. Activated carbon is used for

a) Disinfection

b) Removing hardness

c) Removing odours

d) Removing corrosiveness


Q17. The suitable layout of a distribution system for irregularly growing town is

a) Dead end system

b) Grid iron system

c) Radial system

d) Ring system


Q18. The suitable layout of distribution system for a city with roads of rectangular pattern is

a) Grid iron system

b) Dead end system

c) Ring system

d) Radial system


Q19. Hardy cross method of analysis of distribution system

I) involves successive trials

Ii) takes economic aspects into account

Iii) is time consuming

The correct answer is

a) Only (i)

b) (i)and(ii)

c) (i) and (iii)

d) All are correct


Q20. Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system?

a) Circle method

b) Equivalent pipe method

c) Hardy cross method

d) Electrical analysis method


Part 16: Objective questions and answers of Environmental Engineering


Q1. Answer c


Q2. Answer d


Q3. Answer d


Q4. Answer a


Q5. Answer a


Q6. Answer a


Q7. Answer c


Q8. Answer a


Q9. Answer c


Q10. Answer d


Q11. Answer c


Q12. Answer a


Q13. Answer a


Q14. Answer a


Q15. Answer b


Q16. Answer c


Q17. Answer a


Q18. Answer a


Q19. Answer c


Q20. Answer b