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)

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)
by

1 Answer

Answer :

(D) All (A), (B) and (C)
by

Related questions

(3) Conversion of ammonia to nitrites Explanation: Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria AOB) and ammonia-oxidizing archaea (AOA). Nitrification is an important step in the nitrogen cycle in soil.

Description : (3) Conversion of ammonia to nitrites Explanation: Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The oxidation of ammonia ... -oxidizing archaea (AOA). Nitrification is an important step in the nitrogen cycle in soil.

Last Answer : Acid rain is caused due to pollution of atmosphere by – (1) oxides of carbon and nitrogen (2) oxides of nitrogen and sulphur (3) oxides of nitrogen and phosphorous (4) None of these

Biological oxidation ponds remove organic matters present in the polluted water by (A) Using the activities of bacteria and other micro organisms (B) Aerobic oxidation (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Biological oxidation ponds remove organic matters present in the polluted water by (A) Using the activities of bacteria and other micro organisms (B) Aerobic oxidation (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Nitrification is the biological process of converting – (1) N9 into nitrate (2) N2 into nitrite (3) Ammonia into nitrite (4) Ammonia into N2

Description : Nitrification is the biological process of converting – (1) N9 into nitrate (2) N2 into nitrite (3) Ammonia into nitrite (4) Ammonia into N2

Last Answer : (3) Ammonia into nitrite Explanation: Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The transformation of ammonia ... limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil.

Nitrification is the biological process of converting (1) N2 into nitrate (2) N2 into nitrite (3) Ammonia into nitrite (4) Ammonia into N2

Description : Nitrification is the biological process of converting (1) N2 into nitrate (2) N2 into nitrite (3) Ammonia into nitrite (4) Ammonia into N2

Last Answer : Ammonia into nitrite

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 the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)? (A) Lagooning (B) Activated carbon adsorption (C) Biological oxidation pond (D) Chemical coagulation

Description : Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)? (A) Lagooning (B) Activated carbon adsorption (C) Biological oxidation pond (D) Chemical coagulation

Last Answer : (B) Activated carbon adsorption

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)

Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere? (a) Aerobic nitrate oxidation and nitrite reduction (b) Decomposition of organic nitrogen and conversion of dinitrogen to ammonium compounds (c) Enteric fermentation in cattle and nitrogen fixation by Rhizobium in root nodules of legumes (d) Anaerobic ammonium oxidation and denitrification

Description : Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere? (a) Aerobic nitrate oxidation and nitrite reduction (b) ... fixation by Rhizobium in root nodules of legumes (d) Anaerobic ammonium oxidation and denitrification

Last Answer : (d) Anaerobic ammonium oxidation and denitrification

Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted waterstream?(A) Sedimentation tank(B) Circular clarifier(C) Mechanical flocculation(D) Chemical coagulation

Description : Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted waterstream? (A) Sedimentation tank (B) Circular clarifier (C) Mechanical flocculation (D) Chemical coagulation

Last Answer : (D) Chemical coagulation

Which of the process is known as nitrification? (1) Reaction of Nitrogen Monoxide with oxygen to form nitric acid (2) Reaction of nitrogen dioxide with water to form nitric acid (3) Conversion of ammonia to nitrites (4) Conversion of nitrite to nitric oxide

Description : Which of the process is known as nitrification? (1) Reaction of Nitrogen Monoxide with oxygen to form nitric acid (2) Reaction of nitrogen dioxide with water to form nitric acid (3) Conversion of ammonia to nitrites (4) Conversion of nitrite to nitric oxide

Last Answer : Conversion of ammonia to nitrites

The main process to purify water by filtration, is (A) Mechanical straining (B) Flocculation and sedimentation (C) Biological metabolism (D) All the above

Description : The main process to purify water by filtration, is (A) Mechanical straining (B) Flocculation and sedimentation (C) Biological metabolism (D) All the above

Last Answer : (D) All the above

Which is the most practical and economical method for removal of suspended solid matter from polluted water? (A) Sedimentation (B) Skimming off (C) Chlorination (D) Biological oxidation

Description : Which is the most practical and economical method for removal of suspended solid matter from polluted water? (A) Sedimentation (B) Skimming off (C) Chlorination (D) Biological oxidation

Last Answer : (A) Sedimentation

Radioactive substances present in the polluted water stream can be removed by (A) Biological oxygen treatment (B) Coagulation and filtration (C) Adsorption in ion exchange materials (D) None of these

Description : Radioactive substances present in the polluted water stream can be removed by (A) Biological oxygen treatment (B) Coagulation and filtration (C) Adsorption in ion exchange materials (D) None of these

Last Answer : (C) Adsorption in ion exchange materials

If Organic sources of carcinogenic compounds in water persist even after chlorination, then what is the correct sequence among treatment processes listed below if all these are considered compulsory ? 1. Coagulation 2. Sedimentation 3. Filtration in general 4. Activated carbon bed filtration 5. Flocculation 6. Chlorination a) 4-5-3-2-6 and 1 b) 1-2-3-4-5 and 6 c) 4- 2- 3- 1- 5 and 6 d) 1-5-2-3-4 and 6

Description : If Organic sources of carcinogenic compounds in water persist even after chlorination, then what is the correct sequence among treatment processes listed below if all these are considered compulsory ? 1. Coagulation 2. Sedimentation 3. Filtration in ... c) 4- 2- 3- 1- 5 and 6 d) 1-5-2-3-4 and 6

Last Answer : d) 1-5-2-3-4 and 6

The main role of bacteria in the carbon cycle involves (a) chemosynthesis (b) digestion or breakdown of organic compounds (c) photosynthesis (d) assimilation of nitrogenous compounds.

Description : The main role of bacteria in the carbon cycle involves (a) chemosynthesis (b) digestion or breakdown of organic compounds (c) photosynthesis (d) assimilation of nitrogenous compounds.

Last Answer : (b) digestion or breakdown of organic compounds

The main role of bacteria in the carbon cycle involves (a) chemosynthesis (b) digestion or breakdown of organic compounds (c) photosynthesis (d) assimilation of nitrogenous compounds.

Description : The main role of bacteria in the carbon cycle involves (a) chemosynthesis (b) digestion or breakdown of organic compounds (c) photosynthesis (d) assimilation of nitrogenous compounds.

Last Answer : (b) digestion or breakdown of organic compounds

Iron & manganese present in the polluted water is removed by (A) Simple filtration (B) Oxidation followed by settling & filtration (C) Chemical coagulation (D) Chlorination only

Description : Iron & manganese present in the polluted water is removed by (A) Simple filtration (B) Oxidation followed by settling & filtration (C) Chemical coagulation (D) Chlorination only

Last Answer : (B) Oxidation followed by settling & filtration

(2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for determining this amount. This is not a precise quantitative test, although it is widely used as an indication of the organic quality of water.

Description : (2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to ... quantitative test, although it is widely used as an indication of the organic quality of water.

Last Answer : The addition of gypsum to port-land cement helps in : (1) increasing the strength of cement (2) rapid setting of cement (3) preventing rapid setting of cement (4) reduction in the cost of cement

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

Presence of carbonaceous matter in the sewage (A) Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures (B) Reduces sulphate ions to sulphides causing obnoxious smell (C) Increases the quantity of chlorine used for its purification (D) All (A), (B) and (C)

Description : Presence of carbonaceous matter in the sewage (A) Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures (B) Reduces sulphate ions to sulphides causing obnoxious ... quantity of chlorine used for its purification (D) All (A), (B) and (C)

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

Under anaerobic conditions, bacterium Pseudomonas changes (a) Nitrate to molecular nitrogen (b) Nitrate to ammonia (c) Nitrate to nitrite (d) Nitrite to nitrate

Description : Under anaerobic conditions, bacterium Pseudomonas changes (a) Nitrate to molecular nitrogen (b) Nitrate to ammonia (c) Nitrate to nitrite (d) Nitrite to nitrate

Last Answer : Ans. ((a))

Which of the following molecules or ions involved in the Nitrogen Cycle do not contain oxygen atom? (1) Nitrite (2) Ammonia (3) Nitrate (4) Laughing gas

Description : Which of the following molecules or ions involved in the Nitrogen Cycle do not contain oxygen atom? (1) Nitrite (2) Ammonia (3) Nitrate (4) Laughing gas

Last Answer : (2) Ammonia

Urea (a nitrogenous fertiliser) is produced from carbon dioxide and (A) Nitric acid (B) Ammonia (C) Ammonium nitrate (D) Nitric oxide

Description : Urea (a nitrogenous fertiliser) is produced from carbon dioxide and (A) Nitric acid (B) Ammonia (C) Ammonium nitrate (D) Nitric oxide

Last Answer : (B) Ammonia

Nitrogen oxidation (nitrification)refers to the A- conversion of ammonium ions into nitrates through the activities of certain bacteria B- changing of atmospheric nitrogen (N2) to nitrogen compounds C- sulfur is oxidized to the sulfate form through ThiobacillusbacteriaD- none of the above

Description : Nitrogen oxidation (nitrification)refers to the A- conversion of ammonium ions into nitrates through the activities of certain bacteria B- changing of atmospheric nitrogen (N2) to nitrogen compounds C- sulfur is oxidized to the sulfate form through Thiobacillusbacteria D- none of the above

Last Answer : conversion of ammonium ions into nitrates through the activities of certain bacteria

Which of the following is not a natural source of air pollution? (A) Volcanic eruptions and lightening discharges (B) Biological decay of vegetable matter (C) Photochemical oxidation of organic matter (D) None of these

Description : Which of the following is not a natural source of air pollution? (A) Volcanic eruptions and lightening discharges (B) Biological decay of vegetable matter (C) Photochemical oxidation of organic matter (D) None of these

Last Answer : (D) None of these

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

Which of the following is the main nitrogenous waste in humans ? (1) Ammonia (2) Urea (3) Uric Acid (4) Ammonium Nitrate

Description : Which of the following is the main nitrogenous waste in humans ? (1) Ammonia (2) Urea (3) Uric Acid (4) Ammonium Nitrate

Last Answer : Uric Acid

Separation of solid suspended in liquid into a supernatant clear liquid and a denser slurry employs a process termed as the (A) Coagulation (B) Flocculation (C) Sedimentation (D) Clarification

Description : Separation of solid suspended in liquid into a supernatant clear liquid and a denser slurry employs a process termed as the (A) Coagulation (B) Flocculation (C) Sedimentation (D) Clarification

Last Answer : (C) Sedimentation

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

The maximum percentage of CO2 in a flue gas (from a carbonaceous fuel) can be(A) 21(B) 77(C) 79(D) 29

Description : The maximum percentage of CO2 in a flue gas (from a carbonaceous fuel) can be (A) 21 (B) 77 (C) 79 (D) 29

Last Answer : (A) 21

A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2 . It means that (A) 21% excess air has been used for combustion (B) 21% excess oxygen has been used for combustion (C) Complete combustion of fuel has taken place (D) No excess air has been used for combustion

Description : A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2 . It means that (A) 21% excess air has been used for combustion (B) 21% excess oxygen has ... (C) Complete combustion of fuel has taken place (D) No excess air has been used for combustion

Last Answer : (C) Complete combustion of fuel has taken place

The minimum concentration of an electrolyte required to cause coagulation of a sol is called its flocculation value. It is expressed in millimoles per

Description : The minimum concentration of an electrolyte required to cause coagulation of a sol is called its flocculation value. It is expressed in millimoles per

Last Answer : The minimum concentration of an electrolyte required to cause coagulation of a sol is called its ... )` sol so that flocculation just starts ?

In septic tanks, decomposition of organic bacteria, is done by A. Anaerobic bacteria B. Aerobic bacteria C. Both types of bacterias D. None of these

Description : In septic tanks, decomposition of organic bacteria, is done by A. Anaerobic bacteria B. Aerobic bacteria C. Both types of bacterias D. None of these

Last Answer : ANS: A

The organic matter present in soil is known collectively as – (1) Hydrocarbons (2) Podsols (3) Humus (4) Colloids

Description : The organic matter present in soil is known collectively as – (1) Hydrocarbons (2) Podsols (3) Humus (4) Colloids

Last Answer : (3) Humus Explanation: The organic matter present in soil is known collectively as humus. Humus is fully decomposed and finely divided organic matter. Dune is a hill or ridge of sand accumulated and sorted by wind action.

The organic matter present in soil is known collectively as (1) Hydrocarbons (2)Podsols (3) Humus (4)Colloids

Description : The organic matter present in soil is known collectively as (1) Hydrocarbons (2)Podsols (3) Humus (4)Colloids

Last Answer : Humus

which one of the following is not a function of Artificial Kidney? (a) To remove nitrogenous wastes from the blood. (b) To remove excess fluids from the blood. (c) To reabsorb essential nutrients from the blood. (d) To filter and purify the blood.

Description : which one of the following is not a function of Artificial Kidney? (a) To remove nitrogenous wastes from the blood. (b) To remove excess fluids from the blood. (c) To reabsorb essential nutrients from the blood. (d) To filter and purify the blood.

Last Answer : (c) To reabsorb essential nutrients from the blood.

Colloids are purified by (a) Peptisation (b) Coagulation (c) Condensation (d) Dialysis

Description : Colloids are purified by (a) Peptisation (b) Coagulation (c) Condensation (d) Dialysis

Last Answer : Ans:(d)

1. Which disease is caused by bacteria and spread though faecal matter by houseflies? 2. Who is the ex-officio Chairman of Rajya Sabha? 3. Which colloids are solvent loving colloids? 4. Among the Union Territories of India, which one has the largest size? 5. During which reign was the Purana Qila constructed?

Description : 1. Which disease is caused by bacteria and spread though faecal matter by houseflies? 2. Who is the ex-officio Chairman of Rajya Sabha? 3. Which colloids are solvent loving colloids? 4. ... to the formation of the Himalayas? 20. The Maratha power reached its zenith during which Peshwaship?

Last Answer : Answer : 1. Typhoid 2. Vice-President 3. Lyophilic 4. Pondicherry 5. Sher Shah 6. Merv Hughes 7. Disguised 8. Aquarium 9. Tamil Nadu 10. Guru Gobind Singh 11. Regulating Act 12. Metal 13 ... 16. Lausanne 17. Biology and diversity 18. Justice Ramaswami 19. Folding of the geosyncline 20. Balaji II

The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria. (A) Anaerobic (B) Saprophytic (C) Aerobic (D) Parasitic

Description : The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria. (A) Anaerobic (B) Saprophytic (C) Aerobic (D) Parasitic

Last Answer : (C) Aerobic

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

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 

Use of hydrated lime in water treatment (A) Before filtration, reduces the bacterial load on filters (B) After filtration, combats the corrosiveness of water due to the presence of O2 & CO2 (C) Is to adjust the pH value (D) All (A), (B) and (C)

Description : Use of hydrated lime in water treatment (A) Before filtration, reduces the bacterial load on filters (B) After filtration, combats the corrosiveness of water due to the presence of O2 & CO2 (C) Is to adjust the pH value (D) All (A), (B) and (C)

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

Direct reaction of unsaturated hydrocarbons with either NO or NO2 produces an eye irritating pollutant compound known as (A) Photochemical smog (B) Peroxyacetyl nitrate (PAN) or methyl nitrite (C) Benzopyrene (D) Polyacrylonitrile

Description : Direct reaction of unsaturated hydrocarbons with either NO or NO2 produces an eye irritating pollutant compound known as (A) Photochemical smog (B) Peroxyacetyl nitrate (PAN) or methyl nitrite (C) Benzopyrene (D) Polyacrylonitrile

Last Answer : (B) Peroxyacetyl nitrate (PAN) or methyl nitrite

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

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

Last Answer : 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

Presence of __________ bacteria in water causes disease like typhoid. (A) Aerobic (B) Pathogenic (C) Anaerobic (D) Non-pathogenic

Description : Presence of __________ bacteria in water causes disease like typhoid. (A) Aerobic (B) Pathogenic (C) Anaerobic (D) Non-pathogenic

Last Answer : (B) Pathogenic

Nitrogen fixation is a process of - (1) Assimilation of nitrate (2) Utilisation of nitrogen gas (3) Conversion of organic nitrogen to proteins (4) Conversion of molecular nitrogen to ammonia

Description : Nitrogen fixation is a process of - (1) Assimilation of nitrate (2) Utilisation of nitrogen gas (3) Conversion of organic nitrogen to proteins (4) Conversion of molecular nitrogen to ammonia

Last Answer : (4) Conversion of molecular nitrogen to ammonia Explanation: Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH3) or other molecules available ... plants as nutrients. The conversion of organic nitrogen to proteins is achieved in Nitrogen cycle.

Nitrogen fixation is a process of (1) Assimilation of nitrate (2) Utilisation of nitrogen gas (3) Conversion of organic nitrogen to proteins (4) Conversion of molecular nitrogen to ammonia

Description : Nitrogen fixation is a process of (1) Assimilation of nitrate (2) Utilisation of nitrogen gas (3) Conversion of organic nitrogen to proteins (4) Conversion of molecular nitrogen to ammonia

Last Answer : Conversion of molecular nitrogen to ammonia

Deep ponds, in which oxygen is absent except, perhaps, across a relatively thin surface layer, are called : (a) Aerobic ponds (b) Anaerobic ponds (c) Facultative ponds (d) Polishing ponds

Description : Deep ponds, in which oxygen is absent except, perhaps, across a relatively thin surface layer, are called : (a) Aerobic ponds (b) Anaerobic ponds (c) Facultative ponds (d) Polishing ponds

Last Answer : (b) Anaerobic ponds

Nitrogen in water is commonly found in the form of - (1) Nitrous oxide (2) Nitrate (3) Nitric oxide (4) Nitrite

Description : Nitrogen in water is commonly found in the form of - (1) Nitrous oxide (2) Nitrate (3) Nitric oxide (4) Nitrite

Last Answer : (2) Nitrate Explanation: Nitrate (NO3) is the most common form of inorganic nitrogen in unpolluted waters. Nitrate moves readily through soils and into ground water, where concentrations can be much higher than in surface waters. Water in coastal areas mainly contains elementary nitrogen gas (N2).