Waste Water Engineering

41. Discrete or granular particles change their

1. Size
2. Shape
3. Weight
4. None of these

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42. Disposal to sewage in large cities, is done in

1. Irrigation
2. Dilution
3. Oxidation
4. Purification

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43. Dried sewage after treatment is used as

1. Fertilizer
2. Building material
3. Chemical for lowering B.O.D.
4. Base material for paints

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44. Drop manholes are the manholes

1. Without entry ladders
2. Without manhole covers
3. With depths more than 3.5 m
4. Having drains at different levels

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45. Drop manholes at the junctions of sewer lines, are provided if

1. Invert level of a branch sewer is more than 60 cm that of the main sewer
2. Sewer line runs along a main road
3. Ordinary manhole cannot be built
4. Two sewer lines intersect

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46. Dry water flow in a combined sewer, is

1. Industrial sewage
2. Domestic sewage
3. Storm water
4. Inclusive of domestic and industrial sewage but excludes storm water

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47. Dry weather flow is:

1. Average daily rate of flow
2. Average monthly rate of flow
3. Average annual rate of flow
4. Water supply allowance per capita

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48. During preliminary treatment of a sewage

1. Oil and grease are removed from skimming tanks
2. Floating materials are removed by screening
3. Girt and sand are removed by girt chambers
4. All the above

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49. During purification process of sewage the gas given off, is

1. Carbon dioxide
2. Hydrogen
3. Ammonia
4. All the above

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50. Facultative bacteria survive in

1. The presence of oxygen
2. The absence of oxygen
3. Both cases (a) and (b)
4. Neither (a) nor (b)

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