Environmental Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Wastewater Treatment Systems – Nitrification of Ammonia”.
1. Biological oxidation of ammonia is called as ____________
a) Nitrification
b) Denitrification
c) Salination
d) Ammonification
Answer: a
Clarification: Nitrification is the biological oxidation of ammonia to convert into a final product to nitrate, Denitrification is formation of nitrogen gas, salination is the accumulation of free salts, Ammonification is conversion of nitrogen into ammonia.
2. Nitrification of ammonia involves two oxidation stages.
a) True
b) False
Answer: a
Clarification: Nitrification of ammonia is a biological oxidation stage where ammonia is converted into nitrite followed by the oxidation of the nitrite into nitrate but the conversion of ammonia to nitrite is a rate limiting step of nitrification.
3. Which of the following metal catalyst is not used during catalytic oxidation of ammonia?
a) Platinum
b) Copper
c) Nickel
d) NaCl
Answer: d
Clarification: Platinum, Copper and Nickel is used as a metal catalyst during catalytic oxidation of ammonia, NaCl is a salt and hence, cannot be used as a metal catalyst.
4. _____________ bacteria get the energy from oxidation of inorganic nitrogen compounds.
a) Organic pollutant
b) Fish biomass
c) Nitrifying bacteria
d) Pathogenic bacteria
Answer: c
Clarification: Nitrifying bacteria oxidizes inorganic nitrogen compounds resulting in the formation of nitrate, Pathogenic bacteria are harmful to living organisms and humans, Organic pollutant is a persistent pollutant in the environment, fish biomass includes living biological organisms, Oxygen is required for oxidation process and water is not decreased.
5. Which of the following bacteria is involved in nitrification of ammonia?
a) Nitrite oxidizing bacteria
b) Denitrifying bacteria
c) Pathogenic bacteria
d) Fat stabilizing bacteria
Answer: a
Clarification: Both ammonia oxidizing bacteria and nitrite oxidizing bacteria are involved in oxidation of inorganic nitrogen compounds, Denitrifying bacteria are involved in the later stages of conversion into nitrogen, Pathogenic bacteria are harmful to living organisms and humans, fat stabilizing bacteria stabilizes the gut of humans.
6. Bacteria eat a lot of ammonia produced in the fish gills.
a) True
b) False
Answer: a
Clarification: Bacteria eat the ammonia that is produced in the fish gills which the fish produces as a waste product during their protein metabolism, ammonia being toxic, pollutes the water, hence, can be degraded by the bacteria.
7. The optimum growth temperature of nitrifying bacteria is __________
a) 77-86° F
b) 64° F
c) 32° F
d) 46-50° F
Answer: a
Clarification: The optimum temperature required for the growth of nitrifying bacteria is 77-86° F, growth decreases by 50% at 64° F, growth decreases by 75% at 46-50° F and bacteria will die at 32° F.
8. Nitrifying bacteria cannot survive at 0° C.
a) True
b) False
Answer: a
Clarification: Nitrifying bacteria dies at 32° F and the optimum temperature required for the growth of nitrifying bacteria is 77-86° F.
9. Nitrogen is returned back into the atmosphere by the activity of _________
a) Decomposers
b) Dead organisms
c) Nitrifying bacteria
d) Pathogenic bacteria
Answer: a
Clarification: Decomposers break down the complex nitrogen compounds present in dead organisms and returns it back into the atmosphere, Dead organisms are degraded, Nitrifying bacteria converts ammonia, Pathogenic bacteria infects organisms.
10. Nitric acid is formed during oxidation of ammonia.
a) True
b) False
Answer: a
Clarification: Nitric acid is formed during oxidation of ammonia, oxygen added can oxidize the ammonia and forms nitric oxide which when mixed with water, forms nitric acid.