Environmental Engineering Multiple Choice Questions on “Biological Characteristics of Waste Water”.
1. Which of the following is an end product formed from both the aerobic and anaerobic decomposition of organic matter?
a) NO3
b) CH4
c) H2S
d) CO2
Answer: d
Clarification: Carbon dioxide is formed due to the oxidation and reduction of organic matter by aerobic and anaerobic bacteria respectively.
2. The aerobic decomposition of carbonaceous organic matter gives __________
a) Nitrites and water
b) Carbon dioxide and water
c) Sulfates and water
d) Nitrogen and Ammonia
Answer: b
Clarification: Carbonaceous organic matter (oxidation by aerobic bacteria) —–> CO2 + H2O + Energy.
3. BOD of wastewater having aerobic oxidation is more than that, having anaerobic oxidation.
a) True
b) False
Answer: b
Clarification: The BOD of wastewater where oxidation of organic matter takes place is very less in comparison to that formed by anaerobic oxidation, where BOD of 5000ppm can be formed.
4. The aerobic decomposition of nitrogenous organic matter gives __________
a) Nitrites and water
b) Carbon dioxide and water
c) Nitrates and ammonia
d) Nitrogen and ammonia
Answer: c
Clarification: Nitrogenous organic matter (oxidation by aerobic bacteria) —–> NO–3 + NH3 + Energy.
5. Methane is formed due to the reduction of __________
a) Nitrates
b) Sulfates
c) Carbon dioxide
d) Organic acids
Answer: d
Clarification: Organic acids (oxidation by anaerobic bacteria) —–> CH4 + CO2 + Energy.
6. Which of the following is formed due to the anaerobic decomposition of carbonaceous organic matter?
a) Nitrites
b) Carbon dioxide
c) Water
d) Nitrogen
Answer: b
Clarification: Carbonaceous organic matter (reduction by anaerobic bacteria) —–> CO2 + Energy.
7. Which of the following is formed due to the reduction of sulfurous organic matter?
a) Hydrogen sulfide
b) Hydrochloric acid
c) Sulfuric acid
d) Sulfur dioxide
Answer: a
Clarification: Sulfurous organic matter (reduction by anaerobic bacteria) —–> H2S + Energy.
8. Partially oxidized sewage contains __________
a) Nitrites and Nitrates
b) Nitrates and sulfur
c) Sulfates and nitrates
d) Nitrites and sulfur
Answer: d
Clarification: Partially oxidized sewage contains nitrites and sulfur whereas fully oxidized sewage contains nitrates and sulfates.
9. The aerobic decomposition of sulfurous organic matter gives __________
a) Nitrites and water
b) Carbon dioxide and water
c) Sulfates and water
d) Nitrogen and Ammonia
Answer: c
Clarification: Sulfurous organic matter (oxidation by aerobic bacteria) —–> SO–4 + Energy.
10. The energy released during the aerobic oxidation of organic matter is _____ kilo calories.
a) 26
b) 254
c) 360
d) 484
Answer: d
Clarification: Large amount of energy is released during the oxidation of organic matter with a magnitude between 484 and 674 kilo calories.
11. The decomposition of nitrogenous organic matter in the absence of oxygen gives __________
a) Nitrites and water
b) Carbon dioxide and water
c) Nitrates and ammonia
d) Nitrogen, ammonia and organic acids
Answer: d
Clarification: Nitrogenous organic matter (reduction by anaerobic bacteria) —–> N2 + NH3 + organic acids + Energy.
12. Which of the following is formed from the anaerobic oxidation of organic matter?
a) NO3
b) SO4
c) H2S
d) NH2
Answer: c
Clarification: H2S is formed from the anaerobic oxidation of sulfurous organic matter.
13. The number of stages required for the completion of aerobic oxidation is __________
a) 1
b) 2
c) 3
d) 4
Answer: a
Clarification: Aerobic oxidation gets completed only in single step, whereas anaerobic oxidation gets completed in two steps.
14. Which of the following is formed from oxidation of organic matter in the presence of oxygen?
a) NO3
b) SO4
c) H2S
d) NH2
Answer: a
Clarification: NO3 is formed due to the aerobic decomposition of nitrogenous organic matter.
15. The energy released during the anaerobic oxidation of organic matter is _____ kilo calories.
a) 26
b) 254
c) 360
d) 484
Answer: a
Clarification: Small amount of energy is released during the anaerobic oxidation in comparison to aerobic oxidation of organic matter with a magnitude of 26 kilo calories.