# Civil Engineering - Waste Water Engineering

### Exercise :: Waste Water Engineering - Section 7

6.

The formula used for determining flow velocities in sewers, is known as

 A. Chezy's formula B. Bazin's formula C. Kutter's formula D. Manning's formula.

Explanation:

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7.

The sewage treatment units in which anaerobic decomposition of organic matter is used, are called

 A. imhoff tanks B. trickling filters C. sludge sedimentation tanks D. none of these.

Explanation:

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8.

The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be

 A. 0.9 cm B. 1.2 m C. 1.5 m D. > 1.5 m.

Explanation:

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9.

The most efficient cross section of sewers in a separate sewerage system is

 A. parabolic B. circular C. rectangular D. new egged.

Explanation:

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10.

If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is

 A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l.