Gravity settling tanks/porous filters are used to remove particles larger than

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Gravity settling tanks/porous filters are used to remove particles larger than A. `2 mum ` B. `50 mum` C. `20 mum` D. `10 mum`

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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 : Two particles are called to be equal settling, if they are having the same. (A) Size (B) Specific gravity (C) Terminal velocities in the same fluid & in the same field of force (D) None of these

Last Answer : (C) Terminal velocities in the same fluid & in the same field of force

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Last Answer : (C) Electro-static precipitator

Description : Which is the most efficient dust removal equipment for removal of submicronic dust particles from blast furnace gas? (A) Packed scrubber (B) Gravity settling chamber (C) Electrostatic precipitator (D) Hydrocyclone

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Description : What are used in the direct flow system to transfer the pond batch uniting at intake? a. Separators b. Filters c. Baffle walls d. Porous pipes

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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

Last Answer : ANS: D

Description : Rapid gravity filters can remove bacterial impurities up to a maximum of  (A) 50 %  (B) 60 %  (C) 70 %  (D) 80 %

Last Answer : (D) 80 %

Description : Aquarium newbie here: Do fish tanks with filters still need water changes frequently?

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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

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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

Last Answer : ANS: B

Description : Low temperature oxidation of coal is accelerated by the (A) Storage in large heaps (B) Storage in compressed piles (C) Absence of porous or friable particles (D) All (A), (B) and (C)

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Description : Pick up the correct statement from the following: (A) According to the petrological characteristics, concrete aggregates are classified as heavy weight, normal weight and light weight (B) According to ... glassy, smooth, granular, rough, crystalline, honey combed and porous (D) All the above

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Description : A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is (A) 0.90 μm/s (B) 1 μm/s (C) 22.1 μm/s (D) 0.02 μm/s

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Description : Sorting classifiers employing differential settling methods forseparation of particles make use of the differences in their (A) Particle sizes (B) Densities (C) Terminal velocities (D) None of these

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Description : In classification, particles are said to be equal settling, if they have the same terminal velocities in the (A) Different fluids (B) Same fluid (C) Same field of force (D) Both (B) and (C)

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Description : Gravity settling process is not involved in the working of a (A) Hydrocyclone (B) Classifier (C) Dorr-thickener (D) Sedimentation tank

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Description : If the specific gravity of a soil particle of 0.05 cm diameter is 2.67, its terminal velocity while settling in distilled water of viscosity, 0.01 poise, is (A) 0.2200 cm/sec (B) 0.2225 cm/sec (C) 0.2250 cm/sec (D) 0.2275 cm/sec

Last Answer : (D) 0.2275 cm/sec

Description : Which of the following does not discharge the dust collected as a dry solid? (A) Electrostatic precipitator (B) Wet scrubber (C) Bag filter (D) Gravity settling chamber

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Description : Which of the following statements is true regarding contracts? Select one: a. They are the filters through which project members screen information that is shared. b. They do not lend ... information-rich  environment will suffer. e. Contracts promote the growth of a trusting project culture.

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Description : Pick up the correct statement from the following: (A) Sand obtained from pits, is washed to remove clay and silt (B) Sand obtained from flooded pits, need not be washed before use (C) The ... shore sand and shingle may cause corrosion of reinforcement if the concrete is porous (D) All the above

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Description : The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by (A) Biological oxygen pond (B) Aerated lagoons (C) Trickling filters (D) Gravity separator having oil skimming devices

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Description : Rapid gravity filters  (A) Were developed by G.W. Fuller  (B) Make use of coarser sand with effective size as 0.5 mm  (C) Yield as high as 30 times the yield of slow sand filters  (D) All the above 

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Last Answer : Need answer

Description : How the particle theory of matter to explain how sedimentation tanks help to remove solid wastes?

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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

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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

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Last Answer : (C) 0.7

Description : Which of the following dust collection equipments is the least efficient (for sub-micronic particles)? (A) Dust catcher (gravity type) (B) Cyclone separator (C) Bag filter (D) Hollow wet scrubber

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Description : If G is the specific gravity of particles of diameter d, the velocity of settlement V in still water  at T°C, according to Stoke's law, is  (A) V = 418 (G - 1) d² [(3T + 70)/100]  (B) V = 418 (G - 1) d [(3T - ... 1) d² [(2T + 70)/100]  (D) V = 418 (G - 1) d 4  [(3T + 70)/100] 

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Description : A compacted soil sample using 10% moisture content has a weight of 200 g and mass unit weight of 2.0 g/cm3 . If the specific gravity of soil particles and water are 2.7 and 1.0, the degree of saturation of the soil is (A) 11.1 % (B) 55.6 % (C) 69.6 % (D) None of these

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Description : A saturated soil sample has water content of 40% and specific gravity of soil particles 2.7. The void ratio of the soil, is (A) 0.4 (B) 0.52 (C) 1.08 (D) None of these

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Description : A partially saturated sample of soil has a unit weight of 2.0 g/cm3 and specific gravity of soil particles is 2.6. If the moisture content in the soil is 20%, the degree of saturation is (A) 20 % (B) 77 % (C) 92 % (D) None of these

Last Answer : Answer: Option C