Waste Water Engineering

201. The factor responsible for purification of sewage in river is

1. Hydrology
2. Dissolved oxygen in water
3. Temperature
4. All the above

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202. The first stage of neutral process of sludge digestion, is

1. Acid fermentation
2. Acid regression
3. Alkaline fermentation
4. None of these

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203. The flow velocity in detritus tanks is

1. 0.05 m/sec
2. 0.09 m/sec
3. 1.25 m/sec
4. None of these

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204. The following is the physical characteristic of sewage

1. Turbidity
2. Colour
3. Odour
4. All the above

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205. The formula V = (1/n) r2/3

1. Chezy's formula
2. Bazin's formula
3. Kutter's formula
4. Manning's formula

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206. The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning's formula, is given by

1. Bazin
2. Crimp and Bruges
3. William-Hazen
4. Kutter

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207. The gas evolved in sewers is

1. Carbondioxide
2. Hydrogen sulphide
3. Methane
4. All of these

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208. The gas which may cause explosion in sewers, is

1. Carbondioxide
2. Methane
3. Ammonia
4. Carbon monoxide

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209. The gradient of sewers depends upon

1. Velocity of flow
2. Diameter of the sewer
3. Discharge
4. All the above

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210. The grit and silt of the grit chambers, may not be used for

1. Raising low lying areas by dumping
2. Concreting
3. Both (a) and (b)
4. Neither (a) nor (b)

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