Environmental Engineering

161.Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes

1. Foaming
2. Odour nuisances
3. Undesirable plant growth
4. Turbidity

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162.Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N₂ in contaminated air at which it acts as a natural asphyxiate is ≥ _________ percent.

1. 84
2. 88
3. 80
4. 92

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163.Presence of soluble organics in polluted water causes

1. Undesirable plants growth
2. Depletion of oxygen
3. Fire hazards
4. Explosion hazards

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164.Presence of volatile compounds like gasoline, oil, alcohol, ether etc. in municipal sewers may cause

1. Explosion
2. Non biodegradable foam
3. Undesirable plant growth
4. Corrosion

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165.Radioactive solid nuclear wastes are disposed off by

1. High temperature incineration
2. Pathological incineration
3. Pyrolysis
4. Underground burial in concrete containers

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166.Radioactive substances present in the polluted water stream can be removed by

1. Biological oxygen treatment
2. Coagulation and filtration
3. Adsorption in ion exchange materials
4. None of these

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167.Removal of _________ is accomplished by aeration of water.

1. Dissolved gases
2. Suspended solids
3. Dissolved solids
4. None of these

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168.Removal of _________ results from the disinfection of water.

1. Turbidity
2. Odour
3. Hardness
4. Bacteria

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169.Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by

1. Natural aeration of water stream
2. Photosynthetic action of algae
3. Both (A)&(B)
4. Neither (A) nor (B)

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170.Ringelmann chart is used for the evaluation of _________ pollution.

1. Air
2. Water
3. Noise
4. Radioactive

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