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1) A drop manhole is provided if__________________? a. A sewer drops from a height b. A branch sewer joins the main sewer at higher level c. A lamp is inserted to check obstruction d. None of these
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2) ‘Cowl’ is provided at___________________? a. Lower end of ventilating column b. Upper end of ventilating column c. Upper end of the manhole d. First step in manhole
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3) For design of sewers, percentage of sewage discharge is assumed_____________________? a. 65 to 70% b. 70 to 75% c. 75 to 80% d. 85%
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4) 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
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5) If is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, Is_____________________? a. 1.250 D b. 1.350 D c. 1.425 D d. 1.625 D
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6) 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
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7) 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 %
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8) Pick up the in-correct statement from the following? a. Manholes are provided in sewer pipes at suitable intervals b. Catch basins are generally provided in sewers for carrying drainage discharge c. Inlets are generally provided in all sewers d. None of these
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9) 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of_________________? a. 0°C b. 15°C c. 20°C d. 25°C
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10) In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is_______________? a. Separate system b. Combined system c. Partially combined system d. None of these
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11) Dried sewage after treatment is used as____________________? a. Fertilizer b. Building material c. Chemical for lowering B.O.D. d. Base material for paints
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12) In areas where rainy season is limited to a few months, the type of sewerage system recommended is__________________? a. Combined system b. Partially separate system c. Separate system d. None of these
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13) 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 5 to 7.5 cm below the inlet invert level c. The minimum width of septic level is 90 cm d. The depth of tank is kept equal to its width
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14) 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
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15) The pH value of sewage is determined with the help of_________________? a. Imhoff Cone b. Turbid meter c. Potentiometer d. None of these
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16) To maintain aerobic biological activity, the moisture content of the compost mass should be about_________________? a. 45 % b. 50 % c. 55 % d. 60 %
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17) The factor responsible for purification of sewage in river is________________? a. Hydrology b. Dissolved oxygen in water c. Temperature d. All the above
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18) The most efficient cross-section of sewers in a combined sewerage system is________________? a. Parabolic b. Circular c. Rectangular d. New egged
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19) Water content of sewage is about___________________? a. 90 % b. 95 % c. 99 % d. 9.9 %
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20) The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________? a. Bio-Chemical Oxygen Demand (B.O.D.) b. Dissolved Oxygen (D.O.) c. Chemical Oxygen Demand (C.O.D.) d. None of these
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