11. 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
✅ The correct answer is option A.
Environmental Engineering MCQs
12. 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
✅ The correct answer is option A.
13. 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
✅ The correct answer is option A.
14. Assertion A : The consumption of water increases with increase in the distribution pressure. Reason R : Higher distribution pressure causes more loss and waste of water. Select your answer according to 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
✅ The correct answer is option A.
15. The hourly variation factor is usually taken as______________?
A. 1.5
B. 1.8
C. 2.0
D. 2.7
✅ The correct answer is option A.
16. On standard silica scale, the turbidity in drinking water should be limited to_______________?
A. 10 ppm
B. 20 ppm
C. 30 ppm
D. 50 ppm
✅ The correct answer is option A.
17. 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
✅ The correct answer is option A.
18. The slope of sewer shall be__________________?
A. given in the direction of natural slope of ground
B. given in the direction opposite to natural slope of ground
C. zero
D. steeper than 1 in 20
✅ The correct answer is option A.
19. If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to________________?
A. total alkalinity
B. total hardness
C. total hardness – total alkalinity
D. non carbonate hardness
✅ The correct answer is option A.
20. The most common cause of acidity in water is_______________?
A. carbon dioxide
B. oxygen
C. hydrogen
D. nitrogen
✅ The correct answer is option A.