Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess of organic matter.

Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess of organic matter.
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Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess ... true but reason is wrong D. Both are wrong
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High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Description : High value of BOD (Biochemical Oxygen Demand)  indicates that (a) water is less polluted (b) consumption of organic matter in the water is  higher by the microbes  (c) water is pure (d) water is highly polluted.

Last Answer : (b) consumption of organic matter in the water is 

High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Description : High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Last Answer : (b) consumption of organic matter in the water is higher by the microbes

Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: During biodegradation of organic compounds. Oxy

Description : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: During biodegradation of organic compounds. Oxy

Last Answer : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: ... but reason is wrong D. both are wrong

Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Description : Measuring Biochemical Oxygen Demand (BOD) is  a method used for  (a) estimating the amount of organic matter in  sewage water (b) working out the efficiency of oil driven  automobile engines ... commercial  scale (d) working out the efficiency of RBCs about their  capacity to carry oxygen.

Last Answer : (a) estimating the amount of organic matter in  sewage water

Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Description : Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) ... a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Last Answer : (a) estimating the amount of organic matter in sewage water

Biochemical Oxygen Demand (BOD) of sewage is the (a) Oxygen required to oxidise (b) Oxygen required to oxidise biologically inactive organic matter* (c) a and b both (d) none of these

Description : Biochemical Oxygen Demand (BOD) of sewage is the (a) Oxygen required to oxidise (b) Oxygen required to oxidise biologically inactive organic matter* (c) a and b both (d) none of these

Last Answer : (b) Oxygen required to oxidise biologically inactive organic matter*

72. Measuring Biochemical Oxygen Demand (BOD) is a method used for (1) Working out the efficiency of R.B.Cs. about their capacity to carry oxygen (2) Estimating the amount of organic matter is sewage water (3) Working out the efficiency of oil driven automobile engines (4) Measuring the activity of Sacccharomyces cerevisae in producing curd on a commercial scale

Description : 72. Measuring Biochemical Oxygen Demand (BOD) is a method used for (1) Working out the efficiency of R.B.Cs. about their capacity to carry oxygen (2) Estimating the amount of ... driven automobile engines (4) Measuring the activity of Sacccharomyces cerevisae in producing curd on a commercial scale

Last Answer : Estimating the amount of organic matter is sewage water

Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above

Description : Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated ... river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above

Last Answer : ANS: D

Biological Oxygen Demand (BOD) is a measure of: a. Industrial wastes poured into water bodies b. Extent to which water is polluted with organic compounds c. Amount of carbon monoxide inseparably combined with haemoglobin d. Amount of oxygen needed by green plants during night

Description : Biological Oxygen Demand (BOD) is a measure of: a. Industrial wastes poured into water bodies b. Extent to which water is polluted with organic compounds c. Amount of carbon monoxide inseparably combined with haemoglobin d. Amount of oxygen needed by green plants during night

Last Answer : Ans: A

For complete stabilisation of organic matter in polluted water, it takes (A) 5 days (B) 10 days (C) 20 days (D) 30 days

Description : For complete stabilisation of organic matter in polluted water, it takes  (A) 5 days  (B) 10 days  (C) 20 days  (D) 30 days 

Last Answer : (D) 30 days 

The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs) (c) when treated in STPs does not really require the aeration step as the sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Description : The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in ... sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Last Answer : (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)

Assertion: Sewage discharge in a water body causes eutrophication. Reason: This increases the organic content in water body and, hence, the growth of

Description : Assertion: Sewage discharge in a water body causes eutrophication. Reason: This increases the organic content in water body and, hence, the growth of

Last Answer : Assertion: Sewage discharge in a water body causes eutrophication. Reason: This increases the organic content ... Reason are false, then mark (4).

When huge amount of sewage is dumped into a river the BOD will:

Description : When huge amount of sewage is dumped into a river the BOD will:

Last Answer : When huge amount of sewage is dumped into a river the BOD will: A. Increases B. Decreases C. Slightly decreases D. remains unchanged.

Biochemical oxygen demand (BOD) in a river water (a) has no relationship with concentration of oxygen in the water (b) gives a measure of Salmonella in the water (c) increases when sewage gets mixed with river water (d) remains unchanged when algal bloom occurs.

Description : Biochemical oxygen demand (BOD) in a river water (a) has no relationship with concentration of  oxygen in the water (b) gives a measure of Salmonella in the water (c) increases when sewage gets mixed with river  water (d) remains unchanged when algal bloom occurs.

Last Answer : (c) increases when sewage gets mixed with river  water

Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above

Description : Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above

Last Answer : ANS: D

Arrange the following options in ascending order of their BOD value: 1. Sample of highly polluted pond water. 2. Sample from unpolluted pond water. 3.

Description : Arrange the following options in ascending order of their BOD value: 1. Sample of highly polluted pond water. 2. Sample from unpolluted pond water. 3.

Last Answer : Arrange the following options in ascending order of their BOD value: 1. Sample of highly polluted pond water. 2. Sample ... -b-a C. c-a-b D. a-c-b

Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Description : Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an ... 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.075 cumec for a total lift of 12 m, is A. 10 B. 15 C. 20 D. 25 Q No: 44 Aerobic bacterias A. Flourish in the presence of free oxygen B. Consume organic matter as their food C. Oxidise organic matter in sewage D. All the above

Description : The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.075 cumec for a total lift of 12 m, is A. 10 B. 15 C. 20 D. 25 Q No: 44 Aerobic bacterias A. ... presence of free oxygen B. Consume organic matter as their food C. Oxidise organic matter in sewage D. All the above

Last Answer : ANS: D

Pick out the wrong statement.(A) Biological oxygen demand (BOD) is a characteristic and not a constituent of water (B) BOD is a measure of the amount of oxygen which will be demanded & used in 5 days by the biological decomposition of the organic matter present in water stream present as food for the living organism (C) BOD is expressed in mg/litre (typically, BOD=2.5 mg/litre for potable water) (D) None of these

Description : Pick out the wrong statement. (A) Biological oxygen demand (BOD) is a characteristic and not a constituent of water (B) BOD is a measure of the amount of oxygen which will be demanded & used in 5 days ... BOD is expressed in mg/litre (typically, BOD=2.5 mg/litre for potable water) (D) None of these

Last Answer : (D) None of these

Pick out the correct statement. (A) Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water (B) COD is determined by oxidising the organic matter present in water with potassium dichromate in cone, sulphuric acid solution at boiling temperature for specified time (C) COD is related to BOD of a given waste in water but the relationship varies for different wastes. Typically COD of potable water may be 1-2 mg/litre (D) All (A), (B) and (C)

Description : Pick out the correct statement. (A) Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water (B) COD is determined by oxidising the organic matter present in water with potassium dichromate ... of potable water may be 1-2 mg/litre (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Consider the following statements : Activated sludge process can be said to comprise : 1. Conversion of dissolved organic matter into biological flocs 2. Removal of dissolved BOD of the waste water 3. Digestion of the sludge Which of these statements are correct ? (a) 1, 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only

Description : Consider the following statements : Activated sludge process can be said to comprise : 1. Conversion of dissolved organic matter into biological flocs 2. Removal of dissolved BOD of the waste water 3. Digestion of the sludge Which ... 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only

Last Answer : (b) 1 and 2 only

BOD is connected with a) Organic matter b) microbes c) Microbes and Organic matter d) None of the above.

Description : BOD is connected with a) Organic matter b) microbes c) Microbes and Organic matter d) None of the above.

Last Answer : c) Microbes and Organic matter

Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in (A) Coagulation and flocculation of colloids (B) Oxidation of carbonaceous matter to CO2 (C) Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter to the nitrite and eventually to the nitrate (D) All (A), (B) and (C)

Description : Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in (A) Coagulation and flocculation of colloids (B) Oxidation of carbonaceous matter to CO2 (C) ... to the nitrite and eventually to the nitrate (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the (A) Industrial chimney exhaust (B) Automobiles exhaust (C) Photochemical reaction in polluted atmosphere (D) Burning of domestic fuel

Description : Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the (A) Industrial chimney exhaust (B) Automobiles exhaust (C) Photochemical reaction in polluted atmosphere (D) Burning of domestic fuel

Last Answer : (B) Automobiles exhaust

Assertion : Plasmodium vivax is responsible for malaria. Reason : Malaria is caused by polluted water.

Description : Assertion : Plasmodium vivax is responsible for malaria. Reason : Malaria is caused by polluted water.

Last Answer : Assertion : Plasmodium vivax is responsible for malaria. Reason : Malaria is caused by polluted water. ... If both the assertion and reason are false

Aerobic biological oxidation ponds used for the purification of polluted water (A) Destroys/removes pathogen from the sewage (B) Is not very effective for non-biodegradable substances (e.g. ABS) containing effluents (C) Destroys/removes pathogen much more effectively if the sewage is chlorinated (D) All (A), (B) & (C)

Description : Aerobic biological oxidation ponds used for the purification of polluted water (A) Destroys/removes pathogen from the sewage (B) Is not very effective for non-biodegradable substances (e.g. ABS) containing effluents (C) ... much more effectively if the sewage is chlorinated (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Which is correct ascending arragement of BOD of sewage (S) distillery effluent (DE). Paper mill effluent (PE) and sugar mill effluent (SE)

Description : Which is correct ascending arragement of BOD of sewage (S) distillery effluent (DE). Paper mill effluent (PE) and sugar mill effluent (SE)

Last Answer : Which is correct ascending arragement of BOD of sewage (S) distillery effluent (DE). ... B. PEltSltSEltDE C. SltDEltPEltSE D. SEltSltPEltDE

Drained sewage has biological oxygen demand `(BOD)`:

Description : Drained sewage has biological oxygen demand `(BOD)`:

Last Answer : Drained sewage has biological oxygen demand `(BOD)`: A. More than that of water B. Less than that of ... equal to that of water D. None of the above

3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 dayincubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Description : 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 dayincubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Last Answer : ANS: C

If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Description : If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Last Answer : ANS: D

Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from (a) domestic sewage (b) dairy industry (c) petroleum industry (d) sugar industry.

Description : Biochemical Oxygen Demand (BOD) may not be a  good index for pollution for water bodies receiving  effluents from (a) domestic sewage (b) dairy industry (c) petroleum industry (d) sugar industry.

Last Answer : c) petroleum industry

Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from (a) domestic sewage (b) dairy industry (c) petroleum industry (d) sugar industry.

Description : Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from (a) domestic sewage (b) dairy industry (c) petroleum industry (d) sugar industry.

Last Answer : (c) petroleum industry

BOD of raw municipal sewage may be in the range of about __________ mg/litre. (A) 1-2 (B) 5-10 (C) 150-300 (D) 2000-3000

Description : BOD of raw municipal sewage may be in the range of about __________ mg/litre. (A) 1-2 (B) 5-10 (C) 150-300 (D) 2000-3000

Last Answer : (C) 150-300

The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the (A) Bacterial stability factor (B) Relative stability (C) Biological oxygen demand (BOD) (D) Oxygen ion concentration

Description : The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the (A) Bacterial stability factor (B) Relative stability (C) Biological oxygen demand (BOD) (D) Oxygen ion concentration

Last Answer : (B) Relative stability

Use of chlorine in the treatment of sewage (A) Helps in grease separation (B) Increases the biological oxygen demand (BOD) (C) Causes bulking of activated sludge (D) Aids in flocculation

Description : Use of chlorine in the treatment of sewage (A) Helps in grease separation (B) Increases the biological oxygen demand (BOD) (C) Causes bulking of activated sludge (D) Aids in flocculation

Last Answer : (A) Helps in grease separation

Fish die in water bodies polluted by sewage, why? -Do You Know?

Description : Fish die in water bodies polluted by sewage, why? -Do You Know?

Last Answer : answer:

54 Pick up the correct statement from the following: A. The ratio of the quantity of the diluting water to that of the sewage, is known as dilution factor B. The automatic purification of polluted water, is known self purification phenomenon C. The photosynthesis is carried out in the presence of sun light D. All the above

Description : 54 Pick up the correct statement from the following: A. The ratio of the quantity of the diluting water to that of the sewage, is known as dilution factor B. The automatic purification of polluted ... phenomenon C. The photosynthesis is carried out in the presence of sun light D. All the above

Last Answer : ANS: D

Fish die in water bodies polluted by sewage, why?

Description : Fish die in water bodies polluted by sewage, why?

Last Answer : Due to Reduction in oxygen

To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of A. Hydrochloric acid B. Sulphuric acid C. Nitric acid D. Citric acid

Description : To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of A. Hydrochloric acid B. Sulphuric acid C. Nitric acid D. Citric acid

Last Answer : ANS: B

In sewage having fully oxidised organic matter, the nitrogen exists in the form of A. Nitrites B. Nitrates C. Free ammonia D. Aluminoid nitrogen

Description : In sewage having fully oxidised organic matter, the nitrogen exists in the form of A. Nitrites B. Nitrates C. Free ammonia D. Aluminoid nitrogen

Last Answer : ANS: B

In very first stage of decomposition of the organic matter in sewage A. Nitrites are formed B. Nitrates are formed C. Carbondioxide is formed D. Ammonia is formed

Description : In very first stage of decomposition of the organic matter in sewage A. Nitrites are formed B. Nitrates are formed C. Carbondioxide is formed D. Ammonia is formed

Last Answer : ANS: D

For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of A. H2SO4 B. HNO3 C. HCl D. None of these

Description : For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of A. H2SO4 B. HNO3 C. HCl D. None of these

Last Answer : ANS: A

The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these

Description : The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these

Last Answer : ANS: B

Which is not a reason for conservation of water resources. A. The increase in population with the progress of time results in water scarcity. B. Our water resources like the river, lakes etc., are polluted and their water can hardly use without adequate treatment. C. The water demand for industrial use will increase day by day. D. India gets little rain.

Description : Which is not a reason for conservation of water resources. A. The increase in population with the progress of time results in water scarcity. B. Our water resources like the river, lakes etc., are ... C. The water demand for industrial use will increase day by day. D. India gets little rain.

Last Answer : D. India gets little rain.

If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is A. 50 ppm B. 100 ppm C. 150 ppm D. 200 ppm

Description : If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is A. 50 ppm B. 100 ppm C. 150 ppm D. 200 ppm

Last Answer : ANS: D

If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is A. 200 ppm B. 225 ppm C. 250 ppm D. None of these

Description : If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is A. 200 ppm B. 225 ppm C. 250 ppm D. None of these

Last Answer : ANS: C

A river with an inflow of domestic sewage rich in organic waste may result in (a) an increased production of fish due to biodegradable nutrients (b) death of fish due to lack of oxygen (c) drying of the river very soon due to algal bloom (d) increased population of aquatic food web organisms.

Description : A river with an inflow of domestic sewage rich in  organic waste may result in  (a) an increased production of fish due to  biodegradable nutrients (b) death of fish due to lack of oxygen ( ... of the river very soon due to algal bloom (d) increased population of aquatic food web  organisms.

Last Answer : (d) increased population of aquatic food web  organisms.

A river with an inflow of domestic sewage rich in organic waste may result in (a) an increased production of fish due to biodegradable nutrients (b) death of fish due to lack of oxygen (c) drying of the river very soon due to algal bloom (d) increased population of aquatic food web organisms.

Description : A river with an inflow of domestic sewage rich in organic waste may result in (a) an increased production of fish due to biodegradable nutrients (b) death of fish due to lack of oxygen (c) drying of the river very soon due to algal bloom (d) increased population of aquatic food web organisms.

Last Answer : (b) death of fish due to lack of oxygen

Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank. A. Both A and R is true and R is the correct explanation of A B. Both A and R is true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Description : Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank. A. Both A and R is true and R is the correct ... is not a correct explanation of A C. A is true but R is false D. A is false but R is true

Last Answer : ANS: A

Presence of nitrates in water in excess of 50 ppm causes (A) Methemoglobinemia (B) Gastroenteritis (C) Asphyxiation (D) Tooth decay

Description : Presence of nitrates in water in excess of 50 ppm causes (A) Methemoglobinemia (B) Gastroenteritis (C) Asphyxiation (D) Tooth decay

Last Answer : (A) Methemoglobinemia