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
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
Description : If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 250 mg/l
Last Answer : ANS: D
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
Description : With regard to standard of quality of drinking water as laid down by Indian Railway , the requirement (desirable) limit of total dissolved solids should not be more than---------- mg/l a)200 b) 300 c) 400
Last Answer : d) 500*
Description : The concentration of Total Dissolved Solids (TDS) in drinking water should not exceed (A) 500 mg/L (B) 400 mg/L (C) 300 mg/L (D) 200 mg/L
Last Answer : (A) 500 mg/L
Description : 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of A. 0°C B. 15°C C. 20°C D. 25°C
Description : The factor responsible for purification of sewage in river is A. Hydrology B. Dissolved oxygen in water C. Temperature D. All the above
Description : The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known A. Bio-Chemical Oxygen Demand (B.O.D.) B. Dissolved Oxygen (D.O.) C. Chemical Oxygen Demand (C.O.D.) D. None of these
Last Answer : ANS: B
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
Description : Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents
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
Description : The average temperature of sewage in India, is A. 10°C B. 15°C C. 20°C D. 25°C
Description : No treatment of the sewage is given if dilution factor is A. Less than 150 B. Between 150 to 200 C. Between 200 to 300 D. More than 500
Description : Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to A. Initial demand B. First stage demand C. Carbonaceous demand D. All of these
Description : In sewage, the solids in mg per litre is A. 100 to 500 B. 500 to 1000 C. 1000 to 1500 D. 1500 to 2000
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
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)
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)
Description : Ventilating shafts are provided to a sewer line at every A. 100 m B. 150 m C. 200 m D. 300 m
Description : For large sewers, maximum distance between manholes may be A. 50 m B. 100 m C. 200 m D. 300 m
Description : The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is A. 0.05552 cumec B. 0.05554 cumec C. 0.05556 cumec D. 0.0556 cumec
Description : For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm
Description : A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The ... = 283 s (B) t = 356 s (C) t = 400 s (D) t = 800 s
Last Answer : (D) t = 800 s
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
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
Description : 1000 kg of sewage contains A. 0.112 kg in suspension B. 0.112 kg in solution C. 0.225 kg in solution D. Both A. and C. of above
Description : The grit chambers of sewage treatment plants, are generally cleaned after A. 2 days B. 7 days C. 12 days D. 14 days
Description : A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is A. 100 B. 1000 C. 5000 D. 10000
Description : The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is A. 100 cm B. 110 cm C. 120 cm D. 150 cm
Description : In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120. Which portion of the sewage system does not choke in due course of time? A. 100 mm dia. B. 150 mm dia. C. 225 mm dia. D. All of these
Description : Flat rate parcel rates Flat Rate Parcel Boxes size Dimension of boxes (in mm) Weight (in Kg.) Tariff (in Rs.) Small - S 250*50*300 0 to 1 125 Medium - M 250*100*300 Above 1 to 2.5 200 Large - L 300*250*200 Above 2.5 to 5 400
Last Answer : Large - L 300*250*200 Above 2.5 to 5 400
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
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)
Description : Anil played 8 cricket matches. The mean (average) of the runs was found to be 80. After playing four more matches, the mean of the runs of all the matches was found to be 70. The total runs made in the last four matches is (A) 400 (B) 300 (C) 200 (D) 100
Last Answer : Answer: C
Description : The spacing of bars of perforations of fine screens used for the treatment of sewage, is A. 2 to 3 mm B. 3 to 5 mm C. 5 to 8 mm D. 8 to 10 mm
Last Answer : ANS: A
Description : In favourable circumstances a 15 cm concrete cube after 28 days, attains a maximum crushing strength (A) 100 kg/cm2 (B) 200 kg/cm2 (C) 300 kg/cm2 (D) 400 kg/cm
Last Answer : Answer: Option D
Description : Depletion of ozone layer in the outer atmosphere may cause A. Lung cancer B. Skin cancer C. Bronchitis D. Heart disorder
Description : Dissolved oxygen (DO) should not be less than _____________ mg/L of water. (a) 14 (b) 3 (c) 5 (d) 2
Last Answer : Ans:(c)
Description : Inter-distance between ventilation columns in a sewer line is kept A. 25 to 50 m B. 50 m to 100 m C. 100 m to 150 m D. 150 m to 300 m
Description : In 1000 kg of sewage, the total solids approximate A. 0.5 to 1.0 kg B. 1 kg to 2.0 kg C. 5 kg to 7.5 kg D. 7.5 kg to 10 kg
Description : For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed A. 1.5 B. 2.0 C. 2.5 D. 3.0
Description : The design period of sewage treatment works in normally A. 5 – 10 years B. 15 – 20 years C. 30 – 40 years D. 40 – 50 years
Description : The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is A. 1.5 B. 2.0 C. 3.0 D. 4.0
Description : The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is A. 5 m B. 5.5 m C. 6.5 m D. 7 m
Description : For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed A. 1.5 B. 2.0 C. 2.5 D. 3.0
Description : In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is A. 5 B. 10 C. 15 D. 20
Description : The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is A. 1.5 B. 2.0 C. 3.0 D. 4.0
Description : The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope A. 1 in 5 B. 1 in 10 C. 1 in 15 D. 1 in 20
Description : If q is the average sewage flow from a city of population P, the maximum sewage flow A. Q = [(4 + )/(18 + )] q B. Q = [(18 + P)/(4 + )] q C. Q = [(18 + )/(4 + )] q D. Q = [(5 + )/((15 + )] q