Environmental Engineering

191.The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of _________ of water.

1. Dissolved oxygen content
2. Biological oxygen demand
3. Vapor pressure
4. All (A), (B) and (C)

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192.The earth's atmosphere is an envelope of gases present upto a height of about _________ kms.

1. 10
2. 200
3. 1000
4. 2000

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193.The effect of increase in carbon dioxide level of the atmosphere and its profound effect on our climate is called the

1. Catalytic conversion
2. Green house effect
3. Global warming
4. Both (B) and (C)

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194.The function of skimming tank in sewage treatment is to remove _________ substances.

1. Dissolved solid
2. Suspended solid
3. Oil&fatty
4. Gritty&inorganic

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195.The Killer gas which caused Bhopal gas tragedy in 1984 was

1. Phosgene
2. Methyl isocyanate (MIC)
3. Carbon monoxide
4. Sulphur dioxide

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196.The lowest layer of atmosphere is known as the

1. Stratosphere
2. Troposphere
3. Ionosphere
4. None of these

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197.The main industrial source of emission of hydrogen sulphide air pollutant is

1. Petroleum refineries
2. Coal based thermal power plants
3. Pulp and paper plant
4. Metallurgical roasting&smelting plant

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198.The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by

1. Biological oxygen pond
2. Aerated lagoons
3. Trickling filters
4. Gravity separator having oil skimming devices

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199.The main type of sludge gas evolved during sewage treatment in Imhoff tank is

1. CO₂
2. CH₄
3. CO
4. H₂

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200.The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is

1. Pipe vibrations
2. Cavitation
3. Boundary layer separation
4. Fluctuation in liquid flow

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