Description : For efficient working of a sewer, it must be ensured that A. Minimum velocity of 0.45 m/sec, is maintained at its minimum flow B. A maximum velocity of 0.90 m/sec, is maintained at its maximum flow C. Both A. and B. D. Neither A. nor B.
Last Answer : ANS: C
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
Last Answer : ANS: D
Description : Pick up the correct statement from the following: A. The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge B. The sewer pipes of sizes greater than 0.4 m ... discharge C. The minimum design velocity of sewer pipes is taken as 0.8 m/sec D. All the above
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 : 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 : 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 : To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is A. 0.50 m/sec B. 0.60 m/sec C. 0.70 m/sec D. 0.75 m/sec
Description : If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by A. Chezy B. Manning C. Bazin D. Kutter
Description : In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is A. 2.25 B. 2.50 C. 2.55 D. 2.65
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
Last Answer : ANS: A
Description : If the diameter of sewer is 225 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
Description : If the diameter of a sewer is 150 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
Description : The sewerage system consists of A. House sewer B. Lateral sewer C. Branch sewer D. All of these
Description : The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is A. 0.68 m B. 0.88 m C. 1.36 m D. 1.76 m
Description : In detritus tanks, A. Flow velocity is kept 0.09 m/sec B. Detention period is kept 3 to 4 minutes C. Organic and inorganic materials are separated D. All the above
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
Description : A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle ... fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s
Last Answer : (B) 16 mm/s
Description : The self-cleansing velocity of water flowing through pipe lines, is A. 2 metres/sec B. 1 metre/sec C. 0.5 metre/sec D. 0.25 metre/sec
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
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 : Hazen’s formula VS = 418 (GS – Gw)d [(3T + 70)/100] is used for the settlement velocity of the particles of diameter A. Less than 0.01 mm B. Less than 0.05 mm C. Less than 0.1 mm D. Greater than 0.1 mm
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 : Cement concrete sewers are only suitable if non-scouring velocity is between A. 2.5 to 3.0 m/sec B. 3.0 to 4.0 m/sec C. 3.5 to 4.5 m/sec D. 4.5 to 5.5 m/sec
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 : The flow velocity in detritus tanks is A. 0.05 m/sec B. 0.09 m/sec C. 1.25 m/sec D. None of these
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 : The sewer pipe which carries sewage from a building for immediate disposal is A. House sewer B. Lateral sewer C. Intercepting sewer D. Main sewer
Description : A sewer running partially full and hurried with back filled, fails in compression due to A. Weight of the pipe B. Weight of the back fill C. Superimposed traffic loads D. All the above
Description : The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called A. Inverted syphon B. Depressed sewer C. Sag pipe D. all of these
Description : Antisyphonage pipe is fitted A. At the end of septic tanks B. On manholes C. With a W.C. trap D. At the beginning of sewer line
Description : Hydraulic mean radius is A. Mean radius of sewer B. Difference in heads between two points in circular pipes C. Mean of radii in a pipe line of varying cross -sections D. Cross-sectional area/wetted perimeter
Description : In case of sewer lines A. Water test is carried out to check water tightness of the joints B. Test for straightness is carried out with the help of a lamp and mirror C. Obstruction test is carried out with the help of smooth ball of diameter 13 mm D. All the above
Description : If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is A. 1045 mm B. 1065 mm C. 1075 mm D. 1095 mm
Description : The sewer pipes A. Carry sewage as gravity conduits B. Are designed for generating self-cleansing velocities at different discharge C. Should resist the wear and tear caused due to abrasion 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 : 221 For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is A. Cast iron sewers B. Cement concrete sewers C. Glazed bricks sewers D. Stone ware sewers
Description : Maximum permissible velocity 1.5 m/sec, is adopted in drains A. With beds of rocks and gravels B. Lined with stones C. Both A. and B. D. Neither A. nor B.
Description : In sewers the velocity of flow should not be A. More than the self-cleansing velocity B. Less than the self-cleansing velocity C. Less than 10 m/sec D. More than 20 m/sec
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
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 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 : The minimum diameter of sewer to be adopted is A. 10 cm B. 12.5 cm C. 15 cm D. 25 cm
Description : The gradient of sewers depends upon A. Velocity of flow B. Diameter of the sewer C. Discharge D. All the above
Description : In Chezy’s formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is A. D B. D /2 C. D/3 D. D/4
Description : Pick up the correct statement from the following: A. The larger the sewer in size, more will be velocity B. The smaller the sewer in size, less will be velocity C. The larger the sewer in size, no deposition will take place D. The larger the sewer in size, deposition will take place
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
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
Description : You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at A. Full depth B. Half full C. Two third full D. Three fourth full
Description : Pick up the correct statement from the following: A. The boning rod is used for checking the levels of the sewer inverts B. Manhole covers are made circular for the convenience of the cleaning staff C. A manhole is classified as shallow manhole if its depth is less than 0.9 m D. All the above
Description : If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is A. 1.39 m B. 1.49 m C. 1.59 m D. 1.69 m