Description : In a grit chamber of a sewage treatment plant, A. Flow velocity 0.15 m to 0.3 m/sec is kept B. Depth of 0.9 m to 1.20 m is kept C. One minute of detention period is kept D. All the above
Last Answer : ANS: D
Description : If the grit in grit chambers is 4.5 million litres per day, its cleaning is done A. Manually B. Mechanically C. Hydraulically D. Electrically
Last Answer : ANS: A
Description : The recommended detention period for grit chambers is A. 1 minute B. 2 minutes C. 3 minutes D. 5 minutes
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
Description : The grit and silt of the grit chambers, may not be used for A. Raising low lying areas by dumping B. Concreting C. Both A. and B. D. Neither A. nor B.
Last Answer : ANS: B
Description : During preliminary treatment of a sewage A. Oil and grease are removed from skimming tanks B. Floating materials are removed by screening C. Girt and sand are removed by girt chambers D. All the above
Description : Indicate which of the statement is incorrect (a) The detritus tank is type of a grit chamber (b) In detritus tank, velocity of flow is further reduced (c) Grit chambers are provided in the sewage ... to remove the heavier inorganic matter as grit, sand etc. from the sewage (d) None of them*
Last Answer : (d) None of them*
Description : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : For a grit chamber, if the recommended velocity of flow is 0.2 m/sec and detention period is 2 minutes, the length of the tank, is A. 16 m B. 20 m C. 24 m D. 30 m
Last Answer : ANS: C
Description : Dried sewage after treatment is used as A. Fertilizer B. Building material C. Chemical for lowering B.O.D. D. Base material for paints
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
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 : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
Description : Rate of flow of sewage is generally assumed A. More than the rate of water supply B. Equal to the rate of water supply C. Less than the rate of water supply D. At 150 litres per capita
Description : Fresh sewage is generally A. Alkaline B. Acidic C. Highly decomposed D. A source of objectionable odour
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
Description : The coagulant which is generally not used for treating the sewage, is A. Alum B. Ferric chloride C. Ferric sulphate D. Chlorinated copperas
Description : The sewer which transports the sewage to the point of treatment, is called A. House sewer B. Out-fall sewer C. Branch sewer D. Main sewer
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 : Q No: 291 The coagulant widely used for sewage treatment, is A. Alum B. Ferric chloride C. Ferric sulphate D. Chlorinated copperas
Description : The sewage treatment in septic tanks is due to A. Anaerobic decomposition B. Aerobic decomposition C. Parasitic decomposition D. None of these
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 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
Description : The spacing of bars for perforations in coarse screens used for the treatment of sewage, is A. 20 mm B. 30 mm C. 40 mm D. 50 mm
Description : Primary treatment of sewage consists of removal of A. Large suspended organic solids B. Oil and grease C. Sand and girt D. Floating materials
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
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
Description : The sewer that unloads the sewage at the point of treatment is called A. Main sewer B. Outfall sewer C. Branch sewer D. House sewer
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 : 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 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 : 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 : __________ substances present in sewage are removed in grit chamber during sewage treatment. (A) Organic (B) Fatty (C) Inorganic (D) Dissolved
Last Answer : (C) Inorganic
Description : Fine grit present in sewage is removed in the __________ during sewage treatment. (A) Grit chamber (B) Detritus tank (C) Trickling filter (D) Skimming tank
Last Answer : (B) Detritus tank
Description : The small sewers are cleaned by A. Flushing B. Cane rodding C. Wooden pills D. None of these
Description : Pick up the correct statement from the following: A. Small sewers are cleaned by flushing B. Medium sewers are cleaned by cane rodding C. Medium sewers may be cleaned by pills D. All the above
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 : 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 : If the pH value of sewage is 7 A. It is acidic B. It is alkaline C. It is neutral D. None of these
Description : Pick up the correct statement from the following: A. pH value indicates acidity and alkalinity of sewage B. In acidic sewage, the pH value is less than 7 C. In alkaline sewage, the pH value is more than 7 D. All the above
Description : WASTE WATER Engineering Objective Questions Pdf :: Q No: 151 The pH value of fresh sewage is usually A. Equal to 7 B. More than 7 C. Less than 7 D. Equal to zero
Description : Q No: 271 Pick up the correct statement from the following: A. Turbidity is more in strong sewage B. The black colour indicates septic sewage C. The sewage omits offensive odours after four hours D. All the above
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 : The stone ware sewers A. Are used for carrying sewage and drainage from houses B. Are manufactured from clays and shale C. After casting are dried and burnt at temperature 150°C, 700°C and 1200°C D. All the above
Description : A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is A. 2.30 m B. 2.40 m C. 2.45 m D. 2.50 m
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 : 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 : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above
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 : Fresh sewage may become stale in A. One hour B. Two to three hours C. Three to four hours D. Six hours