Description : A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is A. 0.30 m/sec B. 0.35 m/sec C. 0.40 m/sec D. 0.45 m/sec
Last Answer : ANS: D
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
Last Answer : ANS: B
Description : A soil mass coated with a thin layer of paraffin weighs 460 g. When immersed, it displaces 299 cc of water. The weight of paraffin is 10 g. If specific gravity of solids is 2.5 and that of paraffin 0.9, the void ratio of soil, is (A) 0.55 (B) 0.60 (C) 0.65 (D) 0.70
Last Answer : Answer: Option B
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 : 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
Last Answer : ANS: A
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
Last Answer : ANS: C
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
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 determine the specific gravity of soil solids, using a pycnometer of 500 cc., the following data is available : Weight of dry empty pycnometer = 125 g Weight of dried soil and pycnometer = 500 g Weight of dried soil and distilled ... of soil solids, is (A) 2.0 (B) 2.25 (C) 2.50 (D) 2.75
Last Answer : (C) 2.50
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 : To maintain aerobic biological activity, the moisture content of the compost mass should be about A. 45 % B. 50 % C. 55 % D. 60 %
Description : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
Description : The ratio of design discharge to the surface area of a sedimentation tank is called A. Surface loading B. Overflow rate C. Overflow velocity D. All of these
Description : The settlement of a particle in sedimentation tank, is affected by A. Velocity of flow B. Viscosity of water C. Size and shape of solid D. All the above
Description : The maximum depth of sedimentation tanks, is kept A. 3 m B. 3.5 m C. 4 m D. 4.5 m
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
Description : The detention period for plain sedimentation water tanks, is usually A. 4 to 8 hours B. 8 to 16 hours C. 16 to 24 hours D. 24 to 36 hours
Description : In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is A. Q/(B × D) B. Q/(L × D) C. Q/L D. Q/(B × L)
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 discharge per unit plan area of a sedimentation tank, is generally called A. Over flow rate B. Surface loading C. Over flow velocity 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 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 : If a force greater than that of gravity is used to separate solids & fluidsof different densities, the process is termed as the (A) Sedimentation (B) Flocculation (C) Dispersion (D) Centrifugation
Last Answer : (D) Centrifugation
Description : The level of guard rail in bridges shall not be lower than that of running rail by more than a) 25 mm* b) 55 mm c) 75 mm d) 65 mm
Last Answer : a) 25 mm*
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 : Imhoff cone is used to determine A. Settleable solids B. Suspended solids C. Dissolved solids D. None of these
Description : The effluent of a septic tank is A. Fit for discharge into any open drain B. Foul and contains dissolved and suspended solids C. As good as that from a complete treatment D. None of these
Description : Chlorination of water is done for the removal of A. Bacterias B. Suspended solids C. Sediments D. Hardness
Description : For evaporation and measurement of settable solids, the apparatus used, is A. A jar B. A breaker C. A test tube D. An Imhoff cone
Description : Imhoff cone is used to measure A. Total organic solids B. Total solids C. Total in organic solids D. Settleable solids
Description : Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is? A. Centrifugal pump B. Pneumatic ejector C. Reciprocating pump D. None of these
Description : During sewage treatment, effluent from which one of the following treatment units has minimum wt/vol amount of suspended solids? (a) Detritus channel (b) Primary sedimentation tank (c) Secondary sedimentation tank (d) Activated sludge process aeration tank
Last Answer : (d) Activated sludge process aeration tank
Description : Pick up the correct statement from the following: A. The materials separated by screens, is called screenings B. The screenings are disposed off either by burning or by burial or by dumping C. The process of burning the screenings, is known as compositing D. All the above
Description : What is the characteristic impedance of a single wire with a diameter d= 0.25 mm placed at the center between grounded parallel planes separated by 1 mm apart. The wire is held by a material with a velocity factor of 0.75. A. 85 Ω B. 63 Ω C. 50 Ω D. 75 Ω
Last Answer : D. 75 Ω
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 : The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock’s law, is A. Vs = 418 (Gs – Gw) d [(3T + 70)/100] B. Vs = 418 (Gs – Gw)d² [(3T + 70)/100] C. Vs = 218 (Gs – Gw)d² [(3T + 70)/100] D. Vs = 218 (Gs – Gw)d [(3T + 70)/100]
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 : 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 : 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 : 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 : For design of sewers, percentage of sewage discharge is assumed A. 65 to 70% B. 70 to 75% C. 75 to 80% D. 85%
Description : In finish machining of an island on a casting with CNC milling machine, an end mill with 10 mm diameter is employed. The corner points of the island are represented by (0, 0), (0, 30), (50, 30) and (50, 0). By applying cutter radius right ... , 5), (5, 5) d.(5, 5), (45, 5), (45, 25), (5, 25), (5, 5)
Last Answer : a.(-5, 0), (-5, 35), (55, 35), (55,-5), (-5,-5)
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
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 : 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 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 : 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 : 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