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Civil Engineering :: Waste Water Engineering

  1. The settlement velocity of a solid (diameter 0.5 mm, specific gravity 1.75) in water having temperature 10°C, is

  2. A.

     213.5 cm/sec

    B.

     313.5 cm/sec

    C.

     413.5 cm/sec

    D.

     500 cm/sec


  3. For evaporation and measurement of settable solids, the apparatus used, is

  4. A.

     A jar

    B.

     A breaker

    C.

     A test tube

    D.

     An Imhoff cone


  5. As compared to fresh river water, sea water contains oxygen

  6. A.

     10% less

    B.

     20% less

    C.

     10% more

    D.

     20% more


  7. 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

  8. A.

     Full depth

    B.

     Half full

    C.

     Two third full

    D.

     Three fourth full


  9. The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock’s law, is

  10. 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]


  11. Sewer manholes are generally provided at

  12. A.

     The change of gradient

    B.

     The change of direction

    C.

     The junctions of sewers

    D.

     All of these


  13. Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to

  14. A.

     Initial demand

    B.

     First stage demand

    C.

     Carbonaceous demand

    D.

     All of these


  15. The asbestos cement pipes are generally laid

  16. A.

     Horizontally

    B.

     Vertically

    C.

     At an angle of 30°

    D.

     At an angle of 60°


  17. pH value of sludge during alkaline regression stage, is

  18. A.

     More than 7

    B.

     Less than 7

    C.

     Less than 6

    D.

     More than 6


  19. The small sewers are cleaned by

  20. A.

     Flushing

    B.

     Cane rodding

    C.

     Wooden pills

    D.

     None of these