Concept of BOD

Q.

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to the BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L, respectively. Which sample of the water is most polluted?

Can you assign the correct label to each assuming the river water is relatively clean?

Q.

Clean water would have BOD value of less than ?

1. $10\mathrm{ppm}$

2. $20\mathrm{ppm}$

3. $5\mathrm{ppm}$

4. $12\mathrm{ppm}$

Q. Biochemical Oxygen Demand (BOD) is a measure of

1. Industrial wastes poured into water bodies
2. extent to which water is polluted with organic compound
3. amount of carbon monoxide inseperably combined with haemoglobin
4. amount of oxygen needed by green plants during night

Q.

How is the BOD of waste water related to polluting potential?

Q.

Which of the following is/are products of wastewater treatment?

1. Biogas

2. Sludge

3. Both biogas and sludge

4. Aerator

Q. A river with an inflow of domestic sewage rich in organic waste may result in:

1. Drying of the river very soon due to algal bloom.
2. Increased population of aquatic food web organisms.
3. An increased production of fish due to biodegradable nutrients.
4. Death of fish due to lack of oxygen.

Q.

How does the biological oxygen demand get affected with the increased presence of organic matter in water?

1. the oxygen demand remains unchanged

2. None of the above

3. the oxygen demand decreases

4. the oxygen demand increases

Q. The sewage water is treated to ______ BOD.

1. reduce
2. maintain
3. increase
4. none of the above

Q. BOD or Biological Oxygen Demand is the level of oxygen needed in the water body for organisms to survive.

1. True
2. False

Q.

What is NOT true about BOD?

1. It is a result of a biological process

2. Polluted water has high BOD

3. River at its source has high BOD

4. Oxygen is required for the degradation of organic matter

Q. Biochemical oxygen demand in a river water

1. has no relationship with concentration of oxygen in the water
2. gives a measure of the Salmonella in the water
3. increases when sewage gets mixed in the water
4. remains unchanged in the presence of algal bloom

Q. is the amount of dissolved oxygen needed by organisms present in water bodies to digest the organic nutrients present in it.

1. COD
2. LOD
3. BOD
4. MOD

Q.

How does the biological oxygen demand get affected with the increased presence of organic matter in water?

1. The oxygen demand increases

2. The oxygen demand decreases

3. The oxygen demand remains unchanged

4. None of the above

Q. Biological Oxygen Demand (BOD) is a measure of

1. Industrial wastes poured into water bodies.
2. Extent to which water is polluted with organic compounds.
3. Amount of carbon monoxide inseparably combined with haemoglobin.
4. Amount of oxygen needed by green plants during night.

Q. Dumping sewage into the lake ___ the BOD of the water in the lake.

Q. Biochemical Oxygen Demand (BOD) may not be good index for pollution for water bodies receiving effluents from

1. sugar industry
2. domestic sewage
3. dairy industry
4. petroleum industry

Q. Biochemical oxygen demand in a river water

1. has no relationship with concentration of oxygen in the water
2. increases when sewage gets mixed in the water
3. remains unchanged in the presence of algal bloom
4. gives a measure of the Salmonella in the water

Q. A lake with an inflow of domestic sewage rich in organic waste may result in

1. Death of fish due to lack of oxygen
2. Increased population of aquatic food web organisms
3. Drying of the lake very soon due to algal bloom
4. An increased production of fish due to lot of nutrients

Q. Biochemical Oxygen Demand (BOD) may not be good index for pollution for water bodies receiving effluents from :

Q.

What is NOT true about BOD?

1. It is a result of a biological process

2. Polluted water has high BOD

3. River at its source has high BOD

4. Oxygen is required for the degradation of organic matter

Q. In primordial atmosphere when the living organism evolved the respiration process was

1. Anaerobic as it released more energy.
2. Aerobic as it was more complex.
3. Aerobic as it released more energy.
4. Anaerobic because early atmosphere contained little or no oxygen.

Q. BOD or Biological Oxygen Demand is the level of oxygen needed in the water body for organisms to survive.

1. True
2. False

Q. A lake with an inflow of domestic sewage rich in organic waste may result in

1. Death of fish due to lack of oxygen
2. Drying of the lake vary soon due to algal bloom
3. An increased growth of fishes due to lot of nutrients
4. Increased population of aquatic food web organisms

Q.

How does the biological oxygen demand get affected with the increased presence of organic matter in water?

1. The oxygen demand increases

2. The oxygen demand decreases

3. The oxygen demand remains unchanged

4. None of the above

Q. A water body has high BOD, indicating that water is

1. Being contaminated with sewage
2. Being aerated
3. Receiving minerals
4. Atrophic

Q. What is B.O.D.?

1. The amount of $O_2$ utilised by organisms in water.
2. The amount of $O_2$ utilized by microorganisms for decomposition.
3. The total amount of $O_2$ present in water.
4. All of the above.

Q. Dumping sewage into lakes the BOD of the water in the lakes.

1. does not affect
2. increases
3. decreases
4. nullifies

Q. is the amount of dissolved oxygen needed by organisms present in water bodies to digest the organic nutrients present in it.

1. COD
2. LOD
3. BOD
4. MOD

Q. A river with an inflow of domestic sewage rich in organic waste may result in:

1. Drying of the river very soon due to algal bloom.
2. Increased population of aquatic food web organisms.
3. An increased production of fish due to biodegradable nutrients.
4. Death of fish due to lack of oxygen.