Wastewater Treatment MCQ – Environmental Engineering

31. To maintain the aerobic condition of sewage, the sewage is mixed with a large quantity of water is known as

1. Current
2. Sedimentation
3. Oxidation
4. Dilution

32. The efficiency of a sedimentation removal in a continuous sedimentation tank does not depend upon the

1. Discharge through the tank
2. Width of the tank
3. Length of the tank
4. Depth of the tank

33. Strength of sewage is normally given by the concentration of

1. pathogenic organisms
2. phosphorous
3. organic matter
4. sulphates

34. Biological treatment of sewage takes place in

1. grit chamber
2. primary setting tank
3. trickling filter
4. secondary settling

35. The spacing of steel bars in coarse screens used for treatment if sewage is

1. 100 mm
2. 50 mm
3. 40 mm
4. 20 mm

36. Community Waste mostly liquid not containing excreta is specially termed as

1. Garbage
2. Sewage
3. Sewerage
4. Sullage

37. Which of the following process take place during biochemical treatment of sewage effluents?

1. Hydration
2. Reduction
3. Oxidation
4. Carbonation

38. What value of flow is usually considered for designing sewage treatment units?

1. Minimum
2. Maximum
3. Average
4. Harmonic mean

39. A sewage treatment plant mainly consists of 1. Screening 2. Grit removal 3. Secondary sedimentation 4. Aeration and 5. primary sedimentation.

The correct sequence of operations is

1. 1-2-3-4-5
2. 1-2-5-4-3
3. 2-1-4-5-3
4. 2-1-4-3-5
5. 3-4-1-2-5

40. Sewage may be dissposed off without treatment into the water body if the available dilution is

1. < 150
2. > 150
3. > 300
4. < 700
5. > 500