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Civil Engineering :: Waste Water Engineering

  1. A rain sanitary sewer is constructed to carry

  2. A.

     Sanitary sewage

    B.

     Storm sewage

    C.

     Surface water

    D.

     Ground water


  3. Primary treatment of sewage consists of removal of

  4. A.

     Large suspended organic solids

    B.

     Oil and grease

    C.

     Sand and girt

    D.

     Floating materials


  5. For efficient working of a sewer, it must be ensured that

  6. A.

     Minimum velocity of 0.45 m/sec, is maintained at its minimum flow

    B.

     A maximum velocity of 0.90 m/sec, is maintained at its maximum flow

    C.

     Both (A) and (B)

    D.

     Neither (A) nor (B)


  7. In olden days the type of section adopted in trunk and out fall sewers was

  8. A.

     Parabolic shaped

    B.

     Horse shoe shaped

    C.

     Egg shaped

    D.

     Circular shaped


  9. The sewer which collects the discharge from a collecting system and delivers it to a treatment plant, is known

  10. A.

     House sewer

    B.

     Lateral sewer

    C.

     Branch sewer

    D.

     Sewer outfall


  11. Lead acetate test in sewer manhole is done to test the presence of

  12. A.

     Methane gas

    B.

     Hydrogen sulphide

    C.

     Carbondioxide gas

    D.

     Diesel vapours


  13. The sewers

  14. A.

     Must be of adequate size to avoid over flow

    B.

     Must flow under gravity ½ to ¾ full

    C.

     Must be laid at least 2 to 3 m deep to collect /water from the basements

    D.

     All the above


  15. The normal values of over flow rates for sedimentation tanks using coagulant, ranges between

  16. 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


  17. The detention period for plain sedimentation water tanks, is usually

  18. A.

     4 to 8 hours

    B.

     8 to 16 hours

    C.

     16 to 24 hours

    D.

     24 to 36 hours


  19. The minimum recommended diameter of sewers, is

  20. A.

     5 cm

    B.

     10 cm

    C.

     15 cm

    D.

     20 cm