Definition of BOD

Q. Which one of the following statement regarding BOD is true?

1. The greater the BOD of waste water, more is its polluting potential.
2. The greater the BOD of waste water, less is its polluting potential.
3. The lesser the BOD of waste water, more is its polluting potential.
4. The lesser the BOD of waste water, less is its polluting potential

Q. Measuring BOD is a method used for

1. Measuring the activity of Saccharomyces cerevisae in producing curd on a commercial scale
2. Working out the efficiency of RBCs about their capacity to carry oxygen
3. Estimating the amount of organic matter in sewage water
4. Working the efficiency of oil driven automobile engines

Q.

Eutrophication of water bodies which kills fishes leads to depletion of

1. Oxygen

2. Food

3. Essential minerals

4. Light

Q.

How do temperature changes affect living organisms in water?

Q.

What is black water?

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

1. Petroleum industry
2. Sugar industry
3. Domestic sewage
4. Dairy industry

Q.

What happens when sewage mixes with the water body?

Q. The BOD of three samples of water labelled A, B and C were recorded as 20 mg/L, 8mg/L and 400 mg/L, respectively. Which sample of water is the most polluted?

1. Sample A
2. Sample B
3. Both sample A and sample B
4. Sample C

Q. High value of BOD (Biochemical Oxygen Demand) indicates

1. Water is less polluted
2. Water is pure
3. Consumption of organic matter in the water is higher by the microbes
4. None of these

Q. Algal bloom may result in: [1 mark]

1. Biomagnification
2. Eutrophication
3. Biofortification
4. Decrease in BOD

Q. Write the full form of BOD.

Q. Which of the following is a species of weeds that has invaded aquatic habitats and affected aquatic life and biodiversity?

1. Lantana
2. Parthenium
3. Eicchornia
4. Both a and b

Q. The amount of biodegradable organic matter in sewage water can be estimated by measuring

1. Biochemical Oxygen Demand (BOD)
2. The growth of anaerobic bacteria in water
3. Biogeological oxygen demand
4. The growth of aerobic bacteria in water

Q. Which is the correct ascending arrangement of BOD of sewage(S) distillery effluent(DE), paper mill effluent(PE) and sugar mill effluent(SE)?

1. PE$<$S$<$SE$<$DE
2. S$<$DE$<$PE$<$SE
3. SE$<$S<$PE$<$DE
4. SE$<$PE$<$S$<$DE

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

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

Q. what is the difference between fixed dome type biogas plant and floating gas holder type biogas plant

Q. Huge quantity of sewage is dumped in a river. The BOD will.

1. Increase
2. Slightly decrease
3. Decrease
4. Remain unchanged

Q. High BOD indicates

1. Less pollution in water
2. Highly polluted water
3. Less sewage
4. Less microorganisms

Q. BOD of two samples of water A and B were 120 mg/l and 400 mg/l respectively. Which sample is more polluted.

Q. BOD of wastewater is amount of

1. total organic matter
2. oxygen evolution
3. biodegradable organic matter
4. oxygen consumption

Q. Match and find the correct option.

	I		II		III
(a)	BOD	(i)	Supernatant as effluent	(p)	Useful aerobic microbes
(b)	Flocs	(ii)	Measure of organic matter	(q)	All settled solids
(c)	Primary sludge	(iii)	Masses of bacteria associated with fungi	(r)	Methane hydrogen sulphide carbon dioxide
(d)	Biogas	(iv)	Anaerobic sludge digester	(s)	Polluting water has more BOD

1. a-ii-s, b-iii-p, c-i-q, d-iv-r
2. a-ii-p, b-i-r, c-iv-q, d-iii-s
3. a-i-s, b-iii-q, c-iv-p, d-ii-r
4. a-iv-r, b-ii-s, c-iii-p, d-i-q

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

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

Q. Increase of BOD in water leads to

1. Increase in the dissolved O${}_2$ concentration.
2. Decrease in the dissolved O${}_2$ concentration.
3. Maintenance of dissolved O${}_2$ concentration at the same level.
4. No effect on dissolved O${}_2$ concentration.

Q. List the events that reduce the biological oxygen demand (BOD) of a primary effluent during sewage treatment.

Q.

Name the bacteria responsible for polluting the river Ganga.

Q.

The amount of O₂ required by bacteria in water to breakdown wastes into simple inorganic substances is called

1. Biological magnification

2. Eutrophication

3. Oxygen depletion

4. Biological oxygen demand

Q. BOD refers to

1. The amount of oxygen consumed if all the organic matter in $1000ml$ of water were oxidized by bacteria
2. The amount of oxygen released when all the organic matter was consumed by bacteria in $1$ litre of water
3. The oxygen required for bacteria to grow in $1$ litre of effluent
4. The amount of oxygen released if all the organic matter in $1000ml$ of water were oxidized by bacteria

Q. Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to 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 $20mg/L,8mg/L$ and $400mg/L$ 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. Study the lists and find the correct match.

	I		II
(a)	BOD	(i)	Treatment of sewage
(b)	KVIC	(ii)	Measure of organic matter in water
(c)	LAB	(iii)	Biological methods for controlling plant diseases
(d)	STPS	(iv)	Increases vitamin B${}_{12}$
		(v)	Production of biogas

1. a-iv, b-iii, c-ii, d-v
2. a-v, b-ii, c-iii, d-i
3. a-ii, b-i, c-iv, d-v
4. a-ii, b-v, c-iv, d-i

Q. Arrange according to ascending order of BOD.
(a) Highly polluted pond water
(b) Unpolluted pond water
(c) Distilled water

1. b-c-a
2. c-a-b
3. c-b-a
4. a-c-b