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Civil Engineering :: Waste Water Engineering

  1. The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known

  2. A.

     Bio-Chemical Oxygen Demand (B.O.D.)

    B.

     Dissolved Oxygen (D.O.)

    C.

     Chemical Oxygen Demand (C.O.D.)

    D.

     None of these


  3. Removal of oil and grease from sewage, is known

  4. A.

     Screening

    B.

     Skimming

    C.

     Filtration

    D.

     None of these


  5. Are available in size Stoneware sewers

  6. A.

     10 cm

    B.

     15 cm

    C.

     20 cm

    D.

     All the above


  7. Oxidation process results in the formation of

  8. A.

     Carbon dioxide

    B.

     Nitrates

    C.

     Sulphates

    D.

     All the above


  9. The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be

  10. A.

     0.9 cm

    B.

     1.2 m

    C.

     1.5 m

    D.

     > 1.5 m


  11. 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

  12. A.

     0.30 m/sec

    B.

     0.35 m/sec

    C.

     0.40 m/sec

    D.

     0.45 m/sec


  13. In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is

  14. A.

     [(100 + P1)/(100 – P2)] V1

    B.

     [(100 – P1)/(100 + P2)] V1

    C.

     [(100 – P1)/(100 – P2)] V1

    D.

     [(100 + P2)/(100 – P1)] V1


  15. The minimum diameter of sewer to be adopted is

  16. A.

     10 cm

    B.

     12.5 cm

    C.

     15 cm

    D.

     25 cm


  17. In a grit chamber of a sewage treatment plant,

  18. 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


  19. In a trickling filter

  20. A.

     Filtration process is used

    B.

     Biological action is used

    C.

     Neither A nor B

    D.

     Both A and B