Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried out in sludge tank C. The gases produced in sludge digestion process, contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane

Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried out in sludge tank C. The gases produced in sludge digestion process, contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane
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Answer :

ANS: C
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Pick up the correct statement from the following: A. Indore method of composting involves decomposition under aerobic conditions B. Bangalore method of composting involves decomposing under anaerobic conditions C. Fully stabilised refuse by the Bangalore method of compositing is a powdery mass called humus D. all of these

Description : Pick up the correct statement from the following: A. Indore method of composting involves decomposition under aerobic conditions B. Bangalore method of composting involves decomposing under anaerobic conditions C ... the Bangalore method of compositing is a powdery mass called humus D. all of these

Last Answer : ANS: D

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

In a sludge tank, the gas mainly produced, is A. Oxygen B. Nitrogen C. Hydrogen D. Carbon dioxide

Description : In a sludge tank, the gas mainly produced, is A. Oxygen B. Nitrogen C. Hydrogen D. Carbon dioxide

Last Answer : ANS: D

Pick up the incorrect statement from the following for allowing workers to enter sewers A. The particular manhole and one manhole on upstream and one manhole on downstream should remain open for 30 minutes B. Proper tests for the presence of poisonous gases must be carried out C. The men entering the manhole should be advised to smoke in the sewer D. Warning signals should be erected

Description : Pick up the incorrect statement from the following for allowing workers to enter sewers A. The particular manhole and one manhole on upstream and one manhole on downstream should remain open for 30 ... entering the manhole should be advised to smoke in the sewer D. Warning signals should be erected

Last Answer : ANS: C

Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above

Description : Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above

Last Answer : ANS: D

Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Description : Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Last Answer : ANS: C

The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %

Description : The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %

Last Answer : ANS: B

In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days

Description : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days

Last Answer : ANS: C

What gases are produced in anaerobic sludge digesters? (a) Methane and CO2 only (b) Methane, Hydrogen sulphide and CO2 (c) Methane, Hydrogen sulphide and O2 (d) Hydrogen sulphide and CO2

Description : What gases are produced in anaerobic sludge digesters? (a) Methane and CO2 only (b) Methane, Hydrogen sulphide and CO2 (c) Methane, Hydrogen sulphide and O2 (d) Hydrogen sulphide and CO2

Last Answer : (b) Methane, Hydrogen sulphide and CO2

Pick up the incorrect statement from the following: A. The mixture of water and waste products, is called sewage B. The treated sewage effluents, are generally used for irrigating the crops C. The process of collecting, treating and disposing off the sewage, is called sewerage D. The old convergence system was definitely better than water carried sewerage system

Description : Pick up the incorrect statement from the following: A. The mixture of water and waste products, is called sewage B. The treated sewage effluents, are generally used for irrigating the ... is called sewerage D. The old convergence system was definitely better than water carried sewerage system

Last Answer : ANS: D

The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these

Description : The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these

Last Answer : ANS: A

11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days

Description : 11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days

Last Answer : ANS: D

Pick up the incorrect statement from the following: A. Septic tanks are horizontal continuous flow type of sedimentation tanks B. Septic tanks are generally provided a detention period of 12 to 36 hours C. Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases D. None of these

Description : Pick up the incorrect statement from the following: A. Septic tanks are horizontal continuous flow type of sedimentation tanks B. Septic tanks are generally provided a detention period of 12 to 36 hours C ... covered and high vent shafts are provided for the escape of foul gases D. None of these

Last Answer : ANS: D

The detention time (t) of a settling tank, may be defined as the time required for A. A particle to travel along its length B. A particle to travel from top surface to bottom sludge zone C. The flow of sewage to fill the tank D. None of these

Description : The detention time (t) of a settling tank, may be defined as the time required for A. A particle to travel along its length B. A particle to travel from top surface to bottom sludge zone C. The flow of sewage to fill the tank D. None of these

Last Answer : ANS: C

For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these

Description : For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these

Last Answer : ANS: A

If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Description : If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Last Answer : ANS: A

In sewers the gas generally found, is A. Hydrogen sulphide (H2S) B. Carbon dioxide (CO2) C. Methane (CH4) D. All the above

Description : In sewers the gas generally found, is A. Hydrogen sulphide (H2S) B. Carbon dioxide (CO2) C. Methane (CH4) D. All the above

Last Answer : ANS: D

If the flame of a miner’s safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Description : If the flame of a miner’s safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Last Answer : ANS: B

If the flame of a miner’s safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Description : If the flame of a miner’s safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen

Last Answer : ANS: C

The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets

Description : The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets

Last Answer : ANS: D

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

Pick up the correct statement from the following: A. Anaerobic bacteria flourish in the absence of oxygen B. Aerobic bacteria flourish in the presence of oxygen C. Facultative bacteria flourish with or without oxygen D. All the above

Description : Pick up the correct statement from the following: A. Anaerobic bacteria flourish in the absence of oxygen B. Aerobic bacteria flourish in the presence of oxygen C. Facultative bacteria flourish with or without oxygen D. All the above

Last Answer : ANS: D

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

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

Pick up the correct statement from the following: A. The water supply pipes carry pure water free from solid particles B. The water supply pipes get clogged if flow velocity is less than self cleansing velocity C. The sewers may be carried up and down the hills and valleys D. The sewer pipes are generally laid along level hills

Description : Pick up the correct statement from the following: A. The water supply pipes carry pure water free from solid particles B. The water supply pipes get clogged if flow velocity is less than self ... carried up and down the hills and valleys D. The sewer pipes are generally laid along level hills

Last Answer : ANS: A

In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action

Description : In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action

Last Answer : ANS: B

Marsh gas, formed from decaying organic matter and in coal mines is (a) carbon dioxide (b) methane (c) ethane (d) carbon monoxide

Description : Marsh gas, formed from decaying organic matter and in coal mines is (a) carbon dioxide (b) methane (c) ethane (d) carbon monoxide

Last Answer : Ans:(b)

Which of the following gases is produced due to incomplete combustion of fuel? (1) Carbon Dioxide (2) Carbon Monoxide (3) Methane (4) Ethane

Description : Which of the following gases is produced due to incomplete combustion of fuel? (1) Carbon Dioxide (2) Carbon Monoxide (3) Methane (4) Ethane

Last Answer : (2) Carbon Monoxide Explanation: Carbon monoxide (CO) is an odorless, colorless gas formed by the incomplete com bustion of fuels. It is produced from the partial oxidation of carbon-containing com pounds; it forms when there is not enough oxygen to produce carbon dioxide.

Global climate change is being attributed to the atmospheric increase in what two gases produced by human activities? w) ozone and methane x) nitrous oxide and sulfur dioxide y) methane and carbon dioxide z) ozone and carbon monoxide

Description : Global climate change is being attributed to the atmospheric increase in what two gases produced by human activities? w) ozone and methane x) nitrous oxide and sulfur dioxide y) methane and carbon dioxide z) ozone and carbon monoxide

Last Answer : ANSWER: Y -- METHANE AND CARBON DIOXIDE 

Global climate change is being attributed to the atmospheric increase in what two gases produced by human activities? w) oxygen and hydrogen x) ozone and methane y) nitrous oxide and sulfur dioxide z) methane and carbon dioxide e) ozone and carbon monoxide

Description : Global climate change is being attributed to the atmospheric increase in what two gases produced by human activities? w) oxygen and hydrogen x) ozone and methane y) nitrous oxide and sulfur dioxide z) methane and carbon dioxide e) ozone and carbon monoxide

Last Answer : ANSWER: Z -- METHANE AND CARBON DIOXIDE

Skimming tanks are A. Used to remove the grease and oil B. Those from which sludge is skimmed out C. Tanks provided with self- cleansing screens D. Improved version of grit chambers

Description : Skimming tanks are A. Used to remove the grease and oil B. Those from which sludge is skimmed out C. Tanks provided with self- cleansing screens D. Improved version of grit chambers

Last Answer : ANS: A

Which one of the following gases is most significant as air pollutant? A. Carbondioxide B. Oxygen C. Nitrogen D. Sulphur-dioxide

Description : Which one of the following gases is most significant as air pollutant? A. Carbondioxide B. Oxygen C. Nitrogen D. Sulphur-dioxide

Last Answer : ANS: D

The digested sludge from septic tanks, is removed after a maximum period of A. 3 years B. 3.5 years C. 4 years D. 5 years

Description : The digested sludge from septic tanks, is removed after a maximum period of A. 3 years B. 3.5 years C. 4 years D. 5 years

Last Answer : ANS: A

The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres

Description : The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres

Last Answer : ANS: C

Sludge banks are formed if sewage is disposed of in A. Rivers B. Seas C. Lakes D. None of these

Description : Sludge banks are formed if sewage is disposed of in A. Rivers B. Seas C. Lakes D. None of these

Last Answer : ANS: B

pH value of sludge during alkaline regression stage, is A. More than 7 B. Less than 7 C. Less than 6 D. More than 6

Description : pH value of sludge during alkaline regression stage, is A. More than 7 B. Less than 7 C. Less than 6 D. More than 6

Last Answer : ANS: A

The rate of accumulation of sludge in septic tanks is recommended as A. 30 litres/person/year B. 25 litres/person/year C. 30 litres/person/month D. 25 litres/person/month

Description : The rate of accumulation of sludge in septic tanks is recommended as A. 30 litres/person/year B. 25 litres/person/year C. 30 litres/person/month D. 25 litres/person/month

Last Answer : ANS: A

The gas which may cause explosion in sewers, is A. Carbondioxide B. Methane C. Ammonia D. Carbon monoxide

Description : The gas which may cause explosion in sewers, is A. Carbondioxide B. Methane C. Ammonia D. Carbon monoxide

Last Answer : ANS: B

During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above

Description : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above

Last Answer : ANS: D

Oxidation process results in the formation of A. Carbon dioxide B. Nitrates C. Sulphates D. All the above

Description : Oxidation process results in the formation of A. Carbon dioxide B. Nitrates C. Sulphates D. All the above

Last Answer : ANS: D

Select the correct statement from the following. (a) Biogas is produced by the activity of aerobic bacteria on animal waste. (b) Methanobacterium is an aerobic bacterium found in rumen of cattle. (c) Biogas, commonly called gobar gas, is pure methane. (d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Description : Select the correct statement from the following. (a) Biogas is produced by the activity of aerobic bacteria on animal waste. (b) Methanobacterium is an aerobic bacterium found in rumen of ... sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Last Answer : (d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Pick up the incorrect size of stone ware sewers A. 52.5 cm B. 67.5 cm C. 82.5 cm D. None of these

Description : Pick up the incorrect size of stone ware sewers A. 52.5 cm B. 67.5 cm C. 82.5 cm D. None of these

Last Answer : ANS: D

The principal gas evolved from sludge digestion tank is (A) CO(B) CO2 (C) CH4 (D) N2

Description : The principal gas evolved from sludge digestion tank is (A) CO (B) CO2 (C) CH4 (D) N2

Last Answer : (C) CH4

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 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

An organic compound contain 69% carbon and 4.8% hydrogen, the remaining being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20g of this substance is subjected to complete combustion.

Description : An organic compound contain 69% carbon and 4.8% hydrogen, the remaining being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20g of this substance is subjected to complete combustion.

Last Answer : Calculation of mass of CO2 produced: Mass of compound =0.20g %C =12 x C 69=12*mass of CO2 formed*100/44*0.2 Mass of CO2 formed =69*44*.2/12*100 = 0.506g Similarly, % H =2* mass of H2Oformed*100/18* ... compound 4.8=2* mass of H2Oformed*100/18* 0.2 Mass of H2Oformed =4.8*18*0.2/2*100 =0.0864g

Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities. A. Both A and R are true and R is the correct explanation of A B. Both A and R are 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. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other ... of A C. A is true but R is false D. A is false but R is true

Last Answer : ANS: A