Description : An intense rain is falling at a uniform rate of 7.5 cm/hour for a period of 60 minutes on a basin whose area is 500 hectares. If the average infiltration capacity during the entire rain period is assumed to be 1.5 ... of the basin, is (A) 40 cumecs (B) 60 cumecs (C) 80 cumecs (D) 100 cumecs
Last Answer : Answer: Option C
Description : The recommended detention period for grit chambers is A. 1 minute B. 2 minutes C. 3 minutes D. 5 minutes
Last Answer : ANS: A
Description : In case of Imhoff tanks, A. The shape is rectangular B. Detention period is 2 hours C. The velocity of flow is restricted to 0.30 m/minute D. All the above
Last Answer : ANS: D
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
Description : For a continuous flow type of sedimentation tanks A. Width of the tank is normally kept about 6 m B. Length of the tank is normally kept 4 to 5 times the width C. Maximum horizontal flow velocity is limited to 0.3 m/minute D. All the above
Description : The rainfall at any place may be determined by A. Its intensity B. Its direction C. Its frequency D. All the above
Description : A rain sanitary sewer is constructed to carry A. Sanitary sewage B. Storm sewage C. Surface water D. Ground water
Description : Pick up the correct statement from the following: A. Inlets are provided on the road surface at the lowest point for draining rain water B. Inlets are generally provided at an interval of ... along straight roads C. Inlets having horizontal openings, are called horizontal inlets D. All the above
Description : Fresh sewage may become stale in A. One hour B. Two to three hours C. Three to four hours D. Six hours
Last Answer : ANS: C
Description : The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is A. 204 cu.m B. 208 cu.m C. 212 cu.m D. 216 cu.m
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 : The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is A. d² (0.011d + 0.785H)/Q B. d (0.022d + 0.085H)/Q C. d (0.785d + 0.011H)/Q D. d (0.285d + 0.011H)/Q
Description : The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is A. 30 minutes B. 1 hour C. 1 hour and 30 minutes D. 2 hours
Description : Frequency of vibrations is usually expressed in A number of cycles per hour B number of cycles per minute C number of cycles per secondD None of these
Last Answer : C number of cycles per second
Description : Frequency of vibrations is usually expressed in ( A ) number of cycles per hour ( C ) number of cycles per second C ( B ) number of cycles per minute ( D ) None of these
Last Answer : ( C ) number of cycles per second
Description : Drop manholes at the junctions of sewer lines, are provided if A. Invert level of a branch sewer is more than 60 cm that of the main sewer B. Sewer line runs along a main road C. Ordinary manhole cannot be built D. Two sewer lines intersect
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 : If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is A. B. /2 C. /3 D. 2 /3
Description : For providing an Indian type W.C., the R.C.C. slabs in the toilet portion A. Should be sunk by 20 cm B. Should be kept 20 cm above the adjacent portion C. Should be sunk by 50 cm D. Need not be sunk
Description : The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is A. 20 cm B. 25 cm C. 40 cm D. 50 cm
Description : The minimum diameter of sewer to be adopted is A. 10 cm B. 12.5 cm C. 15 cm D. 25 cm
Description : For design purposes, the normal rate of infiltration of ground water into the sewer, is A. 500 litres/km/cm B. 1000 litres/km/cm C. 1500 litres/km/cm D. 2000 litres/km/cm
Description : For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is A. 10 cm B. 12 cm C. 15 cm D. 18 cm
Description : The settlement velocity of a solid (diameter 0.5 mm, specific gravity 1.75) in water having temperature 10°C, is A. 213.5 cm/sec B. 313.5 cm/sec C. 413.5 cm/sec D. 500 cm/sec
Last Answer : ANS: B
Description : For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of A. 100 cm B. 120 cm C. 140 cm D. 160 cm
Description : The minimum recommended diameter of sewers, is A. 5 cm B. 10 cm C. 15 cm D. 20 cm
Description : The minimum diameter of a sewer is kept A. 10 cm B. 15 cm C. 20 cm D. 25 cm
Description : The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be A. 0.9 cm B. 1.2 m C. 1.5 m D. > 1.5 m
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
Description : In septic tanks, A. Free board of 0.3 m may be provided B. The baffles or tees are extended up to top level of scum C. The clear space between the baffle top and covering slab is about 7.5 cm D. All the above
Description : Q No: 101 are available in size Stoneware sewers A. 10 cm B. 15 cm C. 20 cm D. All the above
Description : Which one of the following statements regarding septic tanks is wrong? A. A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided B. The outlet invert level is kept ... . The minimum width of septic level is 90 cm D. The depth of tank is kept equal to its width
Description : If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is A. 100 cm B. 90 cm C. 80 cm D. 50 cm
Description : Bottom openings 15 cm × 15 cm in the standing baffle wall are provided A. 15 cm c/c B. 22.5 cm c/c C. 30 cm c/c D. 50 cm c/c
Description : The coefficient of permeability of soils, is generally expressed in (A) cm/sec (B) cm/minute (C) cm2 /sec (D) cm2 /minute
Last Answer : (A) cm/sec
Description : If intensity of rainfall in cm per hour is I, percentage coefficient of run-off is P, area of catchment in square kilometres is A, the total run-off Q, is given by (A) Q = 1.758 102 API (B) Q = 2.758 ... API (C) Q = 2.758 103 API (D) Q = 2.758 103 A/PI
Last Answer : (C) Q = 2.758 × 103 × API
Description : Izzard formula for the time of concentration in minutes for the plots having no channels, is (where Lo is the length of overland flow in metres and Kp rainfall intensity in cm/hour) (A) T = 111 b. L0 1/3/(Kp)2/3 (B) T = 222 b. L0 1/2/(Kp)1/3 (C) T = 333 b. L0/Kp (D) T = 111 b. L0 1/3/(Kp)2/5
Last Answer : Answer: Option A
Description : The standard B.O.D. of water is taken for A. 1 day B. 2 days C. 3 days D. 5 days
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
Description : Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further ... correct explanation of A C. A is true but R is false D. A is false but R is true
Description : The normal values of over flow rates for secondary sedimentation tanks, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 10,000 litres/sqm/day
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 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 : The normal value of over flow rates for plain primary sedimentation tanks, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 100,000 litres/sqm/day
Description : The normal values of over flow rates for sedimentation tanks using coagulant, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 100,000 litres/sqm/day
Description : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
Description : Sewer manholes are generally provided at A. The change of gradient B. The change of direction C. The junctions of sewers D. All of these
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 : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is A. 1 in 60 B. 1 in 100 C. 1 in 120 D. None of these