250+ TOP MCQs on Biological Treatment of Waste Water – Microbial Removal of Nitrogen and Phosphorous

Environmental Biotechnology written test Questions on “Biological Treatment of Waste Water – Microbial Removal of Nitrogen and Phosphorous”.

1. Which of the following is the main source for eutrophication of surface water?
a) Nitrogen
b) Calcium
c) Magnesium
d) Potassium

Answer: a
Clarification: Nitrogen and phosphorus is majorly responsible for Eutrophication which leads to overgrowth of plants and algae in aquatic ecosystems, after the death of the organisms die, bacterial degradation requires a lot of oxygen consumption leading to hypoxia, Calcium, potassium and magnesium are the basic nutrients and minerals available in the environment not leading to eutrophication.

2. Amino nitrogen and heterocyclic nitrogen can be degraded by biological method by first converting it into ______________
a) Ammonia
b) Nitrate
c) Sulphate
d) Carbon dioxide

Answer: a
Clarification: Amino nitrogen and heterocyclic nitrogen can be degraded by biological method by first converting it into ammonia by aerobic and anaerobic processes thereby making the removal easier, conversion into nitrate has to be again converted into ammonia, and amino nitrogen doesn’t have a sulphate group and it is definitely not converted into carbon dioxide.

3. Which of the following process is not involved in the removal of nitrogen?
a) Nitrification
b) Ammonification
c) Denitrification
d) Desalination

Answer: d
Clarification: Removal of nitrogen from waste water follows 3 basic steps in the following sequence, ammonification, nitrification and denitrification for the complete removal of nitrogen which would otherwise lead to eutrophication, desalination is a procedure by which salt is removed from water bodies, this step is not followed for nitrogen removal.

4. Autotrophic nitrification leads to formation of nitrate by conversion of ammonia.
a) True
b) False

Answer: a
Clarification: Autotrophic nitrification leads to formation of nitrate by conversion of ammonia into nitrate via nitrite with the help of nitrifying bacteria which are aerobic in nature.

5. Which of the following is not an after effect of accumulation of nitrogen and phosphorus in aquatic ecosystem?
a) Adverse health conditions
b) Algal blooms
c) Increase in water quality
d) Reduction in marine life

Answer: c
Clarification: Increase in water quality helps in maintaining a healthy aquatic ecosystem, whereas, Algal blooms causes the reduction in nutrient quality of the water which affects the biological life in water, aquatic organism consumed by humans may cause adverse health issues, nitrogen and phosphorus in aquatic ecosystem leads to eutrophication which leads to algal blooms and other adverse conditions and hence, reduction in marine life.

6. Which of the following genera the nitrifying bacteria doesn’t belong to?
a) Nitrosomonas
b) Nitrosococcus
c) Nitrosospira
d) Pseudomonas

Answer: d
Clarification: Nitrosomonas, Nitrosococcus, Nitrosospira and Nitrosovibrio are various genera of nitrifying bacteria to which they belong, whereas pseudomonas is a different genus which is not involved in nitrification processes.

7. The optimal removal of phosphate by biological method should have a COD/P ratio of 20g COD/g of phosphate.
a) True
b) False

Answer: a
Clarification: For efficient and optimal removal of phosphate by biological method it should have a COD/P ratio of 20g COD/g of phosphate to enhance the good growth of phosphate accumulating bacteria.

8. Ferrous ions can supplement biological phosphate removal.
a) True
b) False

Answer: a
Clarification: Ferrous ions can be added to supplement biological phosphate removal with chemical precipitation, if particulate COD is separated in primary sedimentation pond.

9. Expand OLNAD.
a) Oxygen limited nitrification and denitrification
b) Oxygen reduced nitrification and denitrification
c) Oxygen limited ammonification and denitrification
d) Oxygen reduced nitrification and ammonification

Answer: a
Clarification: OLNAD stands for Oxygen limited nitrification and denitrification where ammonia is removed using organic carbon source in a single step, Oxygen reduced nitrification and denitrification, Oxygen limited ammonification and denitrification and Oxygen reduced nitrification and ammonification are not the correct expansion.

10. The major disadvantage of heterotrophic nitrification is ____________ for final disposal.
a) excess sludge generation
b) less sludge generation
c) presence of oxygen
d) presence of carbon source

Answer: a
Clarification: Heterotrophic bacteria nitrifies the oxidation of inorganic and organic reduced forms of Nitrogen to nitrate which is known as heterotrophic nitrification, excess sludge generation creates a problem and is a major disadvantage of heterotrophic nitrification, whereas, less sludge generation would not create a problem for heterotrophic nitrification, oxygen is required for oxidation process, so, that wouldn’t create a problem, suitable carbon source is required for heterotrophic nitrification.