Waste Water Engineering

31. Bottom openings 15 cm × 15 cm in the standing baffle wall are provided

1. 15 cm c/c
2. 22.5 cm c/c
3. 30 cm c/c
4. 50 cm c/c

View answer

32. Boussinesq's equation for ascertaining unit pressure at a depth 'H' on sewers due to traffic loads, is

1. p_t = 3H³p/2πZ⁵
2. p_t = 2H³p/3πZ⁵
3. p_t = 3H³p/2Z⁵
4. p_t = 2πH³p/3Z⁵

View answer

33. Cement concrete sewers are only suitable if non-scouring velocity is between

1. 2.5 to 3.0 m/sec
2. 3.0 to 4.0 m/sec
3. 3.5 to 4.5 m/sec
4. 4.5 to 5.5 m/sec

View answer

34. Chlorination of water is done for the removal of

1. Bacterias
2. Suspended solids
3. Sediments
4. Hardness

View answer

35. Clogging of sewers, is caused due to

1. Silting
2. Low discharge
3. Greasy and oily matters
4. All the above

View answer

36. 'Cowl' is provided at

1. Lower end of ventilating column
2. Upper end of ventilating column
3. Upper end of the manhole
4. First step in manhole

View answer

37. 'D' is the diameter of circular sewer and 'α' is the side of a square section sewer. if both are hydraulically equivalent, the relationship which holds good, is

1. πD^8/3 = 4 b^8/3
2. πD^3/8 = 4 b^3/8
3. πD^2/3 = 4 b^2/3
4. πD^3/2 = 4 b^3/2

View answer

38. Depletion of ozone layer in the outer atmosphere may cause

1. Lung cancer
2. Skin cancer
3. Bronchitis
4. Heart disorder

View answer

39. Design period of 40 to 50 years is adopted for

1. Branch sewers
2. Main sewers
3. Trunk sewers
4. All the above

View answer

40. Dilution method of disposing of sewage, is not preferred to

1. When sewage is fresh
2. When diluting water has high dissolved oxygen content
3. When diluting water is used for water supply near the point of sewage disposed
4. When the diluting water is having flow currents

View answer