Chemical Environmental Engineering MCQs

141 MCQs  — Chemical Engineering MCQs  (Page 10 of 15)

The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the __________________?
A. Bacterial stability factor
B. Relative stability
C. Biological oxygen demand (bod)
D. Oxygen ion concentration
Presence of soluble organics in polluted water causes_________________?
A. Undesirable plants growth
B. Depletion of oxygen
C. Fire hazards
D. Explosion hazards
Presence of iron and manganese in water causes___________________?
A. Reduction in its dissolved oxygen content
B. Discoloration of bathroom fixtures
C. Temporary hardness
D. None of these
Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in____________________?
A. Coagulation and flocculation of colloids
B. Oxidation of carbonaceous matter to co2
C. Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter
To The nitrite and eventually to the nitrate
Pick out the wrong statement. A. Caustic embrittlement of boiler’s metallic parts is caused by high concentration of caustic soda in boiler feed water___________________?
B. Cooling and freezing of water kills the bacteria present in it
C. With increasing boiler operating pressure of steam, the maximum allowable concentration of
SilIca in feed water goes on decreasing
D. Dissolved oxygen content in high pressure boiler feed water should be nil